These Cobra® Drop-In anchors are a two-step installation anchors that expand using a setting tool. Made of sturdy steel, they are designed for medium-duty of 1146 lb maximum. They require a drill size of 1/2" and a minimum embedment of 1 9/16". It has female internal thread that accepts standard UNC threaded rods with a 16 TPI thread count. Sold in packs of 50 anchors.