Square inserts come in a variety of diameters. Lightweight Round Inserts offer an easy assembly and a high quality finish to a variety of tubular products. Multitrade normally stocks them in metric sizes, and most of them are colored black, except for a few items. LDPE Tube End Inserts provide protection from sharp tube edges and have a secure fitting. Heavy-Duty Round Inserts are ideal as heavy-duty feet for tubular products.