---
product_id: 10179695
title: "Extech RE300 ExStik ORP Meter - Waterproof Oxidation Reduction Potential Tester with Flat Surface Electrode, 1mV Resolution, Memory, and Analog Bargraph for Pool, Spa & Water Quality Analysis"
brand: "extech"
price: "¥45770"
currency: JPY
in_stock: true
reviews_count: 11
category: "Extech"
url: https://www.desertcart.jp/products/10179695-extech-re300-exstik-orp-meter-waterproof-oxidation-reduction-potential-tester
store_origin: JP
region: Japan
---

# IP57 waterproof & floats 1mV resolution precision Stores 15 tagged readings Extech RE300 ExStik ORP Meter - Waterproof Oxidation Reduction Potential Tester with Flat Surface Electrode, 1mV Resolution, Memory, and Analog Bargraph for Pool, Spa & Water Quality Analysis

**Brand:** extech
**Price:** ¥45770
**Availability:** ✅ In Stock

## Summary

> 💧 Measure Like a Pro, Anywhere, Anytime!

## Quick Answers

- **What is this?** Extech RE300 ExStik ORP Meter - Waterproof Oxidation Reduction Potential Tester with Flat Surface Electrode, 1mV Resolution, Memory, and Analog Bargraph for Pool, Spa & Water Quality Analysis by extech
- **How much does it cost?** ¥45770 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/10179695-extech-re300-exstik-orp-meter-waterproof-oxidation-reduction-potential-tester)

## Best For

- extech enthusiasts

## Why This Product

- Trusted extech brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Built to Brave the Elements:** IP57 waterproof design means it floats if dropped—perfect for poolside pros and environmental managers on the go.
- • **Future-Proof Modular Testing:** Easily swap ORP probes for pH or chlorine sensors with automatic recognition—grow your toolkit without buying a new meter.
- • **Smart Memory & Visual Trends:** Recall up to 15 tagged readings instantly and track ORP changes live with a high-contrast LCD and analog bargraph display.
- • **Rugged Flat Surface Electrode:** Say goodbye to fragile glass bulbs; this durable sensor works flawlessly in liquids, semi-solids, and solids for versatile field use.
- • **Lab-Grade Precision at Your Fingertips:** Experience ultra-accurate ORP readings from -999 to 999mV with ±4mV accuracy—no more guesswork in water quality.

## Overview

The Extech RE300 ExStik ORP Meter is a professional-grade, waterproof oxidation-reduction potential tester featuring a rugged flat surface electrode for reliable measurements in diverse media. It offers precise 1mV resolution across a wide range (-999 to 999mV) with ±4mV accuracy, stores up to 15 readings with tags, and displays real-time trends via an analog bargraph. Designed for field durability with an IP57 rating, it floats if dropped in water and supports interchangeable sensor modules for expanded testing capabilities. Ideal for pool, spa, and water quality professionals seeking dependable, lab-quality results on the go.

## Description

Product Description Take the guesswork out of water quality analysis with the Extech RE300 ExStik ORP Meter. Whether you are managing the chlorination of a commercial swimming pool, monitoring cooling towers, treating wastewater, or balancing a complex aquarium ecosystem, measuring your Oxidation-Reduction Potential (Redox) has never been easier or more reliable. Unlike traditional meters with fragile, easily fouled glass bulb sensors, the RE300 features an innovative flat surface electrode. This unique design allows you to obtain highly accurate measurements in liquids, semi-solids, and even solids, all while minimizing maintenance and preventing damage. It delivers a wide measurement range of -999 to 999mV with a high resolution of 1mV, ensuring you get the clinical precision required for professional compliance and environmental testing. Built for the realities of fieldwork, the RE300 boasts an IP57 waterproof housing that literally floats if dropped in water. The smart interface includes an automatic electronic self-calibration function, a digital LCD with a simulated analog bargraph to visually track trends, and an internal memory capable of storing up to 15 readings for quick recall. As an incredibly versatile platform, the base unit features a built-in chip that automatically recognizes interchangeable pH and chlorine probe modules (sold separately), allowing your device to adapt to your future testing needs. Complete with a protective sensor cap, sample cup, batteries, and a neckstrap, this all-in-one kit is ready to elevate your environmental diagnostics from day one. From the Manufacturer The Extech RE300 ExStik ORP Meter measures the ORP/Redox from -999 to 999mV. It has an automatic electronic self calibration and a simulated analog bargraph which displays the change in ORP readings. It has a high resolution of 1mV and a memory that stores and recalls up to 15 readings and it saves the last calibrated value. The data validation indicators show the user that the reading is stabilized and it features data hold, auto shut-off and low battery indication. This meter is waterproof to IP57 which protects the meter from the wet environment. The Extech RE300 ExStik ORP Meter comes complete with a flat surface ORP electrode, a protective sensor cap, a sample cup with a cap, four 3V CR2032 button batteries and a 48 inch neck strap. Incorporated in 1970, Extech Instruments is based in Waltham, Massachusetts USA, just west of Boston. Recognized for the breadth and depth of its Test & Measurement offering and strong distribution network, Extech was acquired by FLIR Systems in November 2007. Extech Instruments’ high-value, handheld test instruments and FLIR-branded infrared thermal imager are sold through a network of national catalog houses, regional stocking distributors, internet, and international master distributors. The company has become one of the largest manufacturers and suppliers of test equipment and portable printers and the Extech Instruments brand is regarded in many industries as the brand of choice. ISO 9001:2000 certified by TUV, Extech’s enviable reputation is built on innovative products that offer unique and patented designs with features, functions and reliability at an affordable price.

Review: Eficiente, práctico y confiable.
Review: Worth it - Accuracy and value for money

## Features

- FLAT SURFACE ELECTRODE: Say goodbye to easily broken glass bulbs. The rugged flat surface sensor allows for quick, on-the-spot ORP and Redox measurements in liquids, semi-solids, and even solids, ensuring reliable contact and superior accuracy.
- HIGH-RESOLUTION ACCURACY: Stop guessing with your water quality. This highly precise digital meter measures from -999 to 999mV with a sharp 1mV resolution and an impressive ±4mV accuracy, giving you laboratory-grade results right in the field.
- FULLY WATERPROOF DESIGN: Never panic about dropping your tool in the pool or tank. Boasting a rugged IP57 waterproof rating, this resilient meter actually floats in water, protecting your investment from accidental submersion and wet environments.
- SMART MEMORY AND DISPLAY: Keep track of your data effortlessly. The built-in memory stores and recalls up to 15 tagged readings, while the high-contrast LCD features a simulated analog bargraph to help you visualize ORP changes in real-time.
- INTERCHANGEABLE SENSOR MODULES: Future-proof your testing toolkit. The smart built-in chip automatically recognizes different probes, allowing you to easily swap the ORP module for pH or chlorine sensors (sold separately) as your needs grow.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B000S8UIVA |
| Batteries | 4 Lithium Metal batteries required. (included) |
| Batteries Included? | Yes |
| Batteries Required? | Yes |
| Battery Cell Type | NiMH |
| Best Sellers Rank | #123,179 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #9 in Dissolved Oxygen Meters & Accessories |
| Color | Blue/Grey |
| Customer Reviews | 4.1 4.1 out of 5 stars (32) |
| Date First Available | June 20, 2007 |
| Description Pile | 4 × CR2032 (3V) batteries |
| Included Components | Meter, Batt, Case |
| Is Discontinued By Manufacturer | No |
| Item Package Quantity | 1 |
| Item Weight | 4.2 ounces |
| Item model number | RE300 |
| Manufacturer | Extech |
| Measurement Accuracy | +/-0.5% |
| Mounting Type | Surface Mount |
| Number Of Pieces | 1 |
| Part Number | RE300 |
| Power Source | Battery Powered |
| Product Dimensions | 0.75 x 0.75 x 200.1 inches |
| Style | RE300 |
| Voltage | 3 Volts |
| Warranty Description | 2 years |

## Product Details

- **Brand:** Extech Instruments
- **Item Weight:** 0.12 Kilograms
- **Battery Description:** 4 × CR2032 (3V) batteries
- **Mounting Type:** Surface Mount
- **Voltage:** 3 Volts

## Images

![Extech RE300 ExStik ORP Meter - Waterproof Oxidation Reduction Potential Tester with Flat Surface Electrode, 1mV Resolution, Memory, and Analog Bargraph for Pool, Spa & Water Quality Analysis - Image 1](https://m.media-amazon.com/images/I/41E6wRYvaLL.jpg)

## Questions & Answers

**Q: Good morning, i would like to know how many probes are included in the instrument? in the second image i see two probes, could i send a real-time imag**
A: Thank you for your question. The full set includes:
Complete with 6 x AA batteries, SD card, hard carrying case,
sample buffers, mini pH electrode (60120B), and Thermistor
temperature probe (850188)

**Q: Can this perform orp readings without orp electrode? or do we have to buy 67500b standard orp electrode additionally? if so can you offer that as well**
A: Yes, you would need to order the orp probe to measure the orp.

**Q: Is this unit capable of continuous immersion logging of typical drinking water to SD card? We'll calibrate every 24 hours, but weekly is better**
A: Thank you so much for your interest in our products. Yes, the SDL100 is capable to datalog information from 1 second to almost 9 hours. All this data will be saved on the SD card. Please notice that the SD card capacity is up to 16GB. Please check all the specifications of this unit here http://www.extech.com/products/resources/SDL100_UM-en.pdf

**Q: What is the settling time for the ORP meter in weak redox solution such as tap water?**
A: It's bad

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by N***E on October 12, 2025*

Eficiente, práctico y confiable.

### ⭐⭐⭐⭐⭐ Worth it
*by S***U on December 12, 2024*

Accuracy and value for money

### ⭐⭐⭐⭐ Worked great, then malfunctioned
*by L***S on June 24, 2021*

For over a month, this ORP meter performed like a champ. The other day, after submerging about 1/2 into water for a test, the meter refused to "Self Check" when turned back on. After disassembly, I found moisture in the compartment where the module plugs into the stick. Blew out, let dry a few hours and the unit returned to self check properly. Today, the unit failed to self check and, upon calling FLIR, the tech ran me through a "software reset" which did not fix the problem. I was then connected to a CSR who asked for my invoice and said that a new unit would be sent to me ASAP. The service was excellent, i received the new item in a timely manner It would appear that this unit is really not well enough designed for regularly swapping out the ORP module with the pH module and maintaining waterproof status. I recommend that you make sure the unit is tightly assembled upon receipt and, if you need a pH meter, to purchase a separate product. I will use this unit to only check ORP and will not submerge beyond the module locking nut.

## Frequently Bought Together

- EXTECH Instruments RE300 ExStik ORP Meter
- Apera Instruments AI1113 pH Calibration Buffer Solution Kit (7.00, 4.00), 8 oz. Each
- Extech DO600 Waterproof ExStik II Dissolved Oxygen Meter

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-04-23*