DC 12V 5RPM 15Kg.cm 8mm Double Shafts Self-Locking Reversible Worm Gear Motor with Cable, High Torque Speed Reduction Motor, Turbine Electric Gearbox Motor

Good quality so far. I used this for a custom gear drive.

great value for the price

I have bought several of these over time and they perform as intended but some have excessive slack in the gear train.

Great little motor so far. Works for what I needed it for.

It is the same worm drive motor in the Rite Hight system for your active target or live scope

Worked as it should

+ Seemed somewhat robust - Doesn't run well at low speeds under PWM control. - Whistles under PWM control using Arduino Uno OC2A/OC2B outputs to drive L298 H-bridge. - Vibrates a lot at full speed, even when run with DC. Unmounted (held in hand) this isn't an issue. When attached to something that functions as a sounding board it seems quite loud. Maybe I can cobble together a sound/vibration dampening mounting system. EDIT 5/19/22: I finally figured out how to use Arduino PWM properly. In phase-correct PWM mode the motor was controllable using a 33khz cycle frequency and a L298 H-bridge. The motor/gearing noise remains at high speeds (if 5rpm can be considered high speed), but all traces of PWM squealing are gone, and speed can be lowered to the point where it's almost imperceptible. So I raised my rating a star. I would have gone to 5 stars but there's a tiny amount of backlash/slop in the output shafts and it's noisier than I would have liked.

After only a few uses it developed slop ! I bought unit to pin point exact direction of a pointer on my transducer and the slop defeats that purpose.