Square Plastic End Caps Blanking Plugs Box Section /Tube Inserts / Black | eBay
30mmx30mm Square Plastic End Caps Blanking Plugs Tube Box Section Inserts/ Black | eBay
China Plastic Molding Profile End Plugs / Square Tubing Pipes Caps / Plastic End Caps for Steel Tube - China Plastic End Caps for Steel Tube, Plastic End Cap for Square Tubing Pipes
Endcap Plastic Inserts 50mm-100mm suit steel box section open ends.