(Pack of 4) 3 Square Plastic Plugs |10 14 Ga - 3 x 3 Inch (for ID 2.74 to 2.83) | Flexible Ridges n Side Walls | Heavy Duty Impact Resistant 1/4 Thick LDPE Cap - Tubing Plugs

They work great. Be sure to get the right ones for the ID. Lots of poor reviews from people who either can’t read or can’t measure.

I USED THESE POST CAPS ON MY POST FOR THE GATE TO MY FARM THEY FIT PERFITLY INTO 3IN 11GA SQUARE TUBING KEEPS THE BEES FROM BUILDING THEIR NEST IN THE POST AND CAPS THEM OFF NICELY FOR A PROFESSNAL LOOK I AM VERY PLEASED WITH THESE POST CAPS AND I RECOMMEND THEM

looks great and fits great

Planned to use for capping a 3x3 steel tube that supports a fence gate. However, the cap isnt large enough to gain enough friction to to anything other that sit on top of the tube. Hope I can find some with larger flexible ridges to hold tighter.