16pcs Pack: 3/4 Inch Square Black Plastic End Cap (for Hole Side Size from 1/2 to 21/32, Including 5/8 inches), Furniture Finishing Plug

I used these inserts on a square tube project I built and they worked perfectly. The fit was nice and tight and the quality was as expected for the price I paid. In my particular case, I was using 3/4" square metal tubing with a thickness of 0.065. I would think that you could easily use these plugs on other thicknesses of metal because the fins on the plugs have flex in them to allow for bending when they are pressed into place.I'd definitely order these parts again.

These worked well to repair some chair/table legs on my outdoor patio furniture that had lost the end caps leaving exposed metal. Just make sure to measure your tubes in order to get the right ones. My patio furniture used 3/4 tubing (external measurement) for the chair/table legs.

I bought these plugs for hollow square metal furniture legs with .500 inch inside dimensions. After shaving off about 1/16” on each side of the barbs I was able to press them in.

These worked perfectly in the stools we refinished

I like that they matched the existing one on my chairs without measuring.

Perfect fit

Used on Jeep JL to help redirect defrost air to the sides of the windshield and it is working.

ToCap off arms on a bar stool