Arrow's T50 3/8-inch staples are made of .050 wire with a 3/8-inch crown and 3/8-inch leg length. They come 1,250 to a pack. Steel - Low Corrosion Resistance. Ideal for indoor applications. T50 staples are the world's best-selling heavy-duty staple platform. Made to deliver exceptional holding power, these staples are used for all heavy-duty stapling applications - from installing insulation, housewraps, and roofing underlayments to upholstering fine furniture and window treatments. A true workhorse of a fastener, Arrow T50 staples are made to precise specifications on state-of-the-art equipment. Compatible with T50, T50HS, 5700, T50X, T50PBN, HT50, HT55, T50ACD, T50DCD, T50AC, PT50, T50RED2. Compatible with Stanley TRA706T.