Xadnitu Beam Clamps, 1/4"-20 Black Steel Bolt-on Beam Clamp Used in Combination with J-Hook, Clamp for Installation on Beams Up to 1/2" Thick (10 Pack)

They fit snug on the underside support beams without any issue. I use them to support ethernet and cable TV cables.

Don't waste your time and energy on these. Weak folded (seams aren't welded) metal can hardly hold its own weight. When you tighten the set screws, the metal frame just bends in on itself.Not even worth returning - threw them right into the trash.

Solid quality

These Xadnitu Beam Clamps are great for hanging lighter objects and particularly conduit, or the like. They are formed from sheet metal, so you probably won't want to hang too many pounds on them, but that also depends on how you are hanging it. If it is clamped onto the horizontal flange of a beam it will hold a bit more than if on a vertical support. There are both threaded and unthreaded holes to work with, facilitating a variety of potential attachments, from pipe/cable J-hook brackets to a machine-threaded pass through eye-bolt or hook that you could even minutely adjust the height of via the nut on the top side, etc. (See the pics I've provided for sizing and spacing, etc.) The electroplated surface is likely to stay that way for a long time without much concern for rust, particularly if it's not directly exposed to the weather. The set screw can be tightened with either a 10mm wrench/socket or a large #3 (PH3) Phillips screwdriver.All said, these Xadnitu Beam Clamps are of great quality for what they are designed for!

I ordered these clamps in an attempt to modify a storage stand that needs a backing. They work great and look to be very durable. The only issue is that the box of clamps is so heavy that the Amazon bag they came in was the only thing from keeping all of the clamps from dropping out.The clamps are nice and sturdy and should be great for all that order them for their purposes.

Immediately bend when you start to tighten… Junk

These metal i-beam clamps have been super easy to work with. There are multiple mounting holes to use to attach your item to on the different sides of the clamp, giving you lots of flexibility in how/where you can mount your equipment to the beam. The screw seems to move easily enough and haven't noticed any issues with the clamps bending. Love having the metal teeth to help grip as well, feels very secure!

Junk threads. They don’t tighten down at all on anything. I will be returning them.