Product Size : Square plastic plugs fit square tubes with an outer diameter of 1-1/2 inches (OD) and an inner diameter of 1.23 inches (31.3mm) to 1.47 inches (37.3mm). Does not apply to pipes with an internal diameter of 1-1/2 inches Premium Quality : The black plastic plug is made of PE (polyethylene) material that is waterproof, abrasion-resistant, durable, and UV-resistant. The plastic end caps are held in place by a series of ribs. Function : The tube end cover not only reduces noise, but also prevents scratches on the floor when moving furniture. You can also bandage the end of the square pipe to prevent it from being hurt and prevent rain rust. A wide range of applications : ribbed plugs can be used as non-slip protection for chair legs, long legs, table legs, bar stools, and swimming pool fences. The square end cap is also suitable for use as a luggage rack end plug-in, fitness equipment end plug-in and other square tube end caps Satisfactory after-sales service : If there is any quality problem with the goods, please feel free to contact us. Your satisfaction is our biggest motivation. Tube end caps not only reduce noise but also prevent scratches to the floor when moving furniture. It also wraps around the end of square tubes to protect them from damage and to keep rainwater from rusting.