Square tube clamp Our clamps are the lifeline to our patented modular mounting system, so we have a solution for all those applications out there with square tubing. We have a variety of clamps for round and square tube applications. The same strength and thin design, but designed to clamp onto those spots with four corners! Get free shipping on qualified Square Clamps products or Buy Online Pick Up in Store today in the Tools Department. Sign in to your Square account to access powerful tools for managing your business. Choose from our selection of square tube clamps, including U-bolts, beam clamps, and more. Its sturdy construction ensures reliable support for a variety of heavy-duty installations Choose from our selection of square tubing connectors, including over 80 products in a wide range of styles and sizes. com. Our extensive collection of fittings, tubing, and caps is designed to accommodate unique square applications that other distributors do not offer. Secure, flexible payment processing software and hardware built to power businesses of every size. Same and Next Day Delivery.