Aluminum square tubing. Shop online today with no minimums and fast shipping! Choose from our selection of aluminum square tubing, including over 225 products in a wide range of styles and sizes. Save money by ordering material cut to length and shipped directly to your door. Aluminum Square Tube products feature either square or radius inside and outside corners. com in standard sizes or custom cut lengths. They are well-suited to structural applications that need lightweight material. Square Tube products are available in a more limited range of sizes than round tube. Metal Supermarkets offers online ordering and in-store cutting service for your metal needs. Same and Next Day Delivery. Compare prices, promotions and availability of various products and services online or in store. Select from a large inventory of cut-to-size aluminum square tubes in various sizes and thicknesses.