Red Head Hammer-Set Nail Drive 3/16 X 7/8 Inch Anchor is a one-piece zinc plated steel anchor that consists of an expansion body and expander drive pin. Anchors meet or exceed GSA specification A-A-1925A Type 1. These anchors install fast and easy through the material that needs to be fastened. They feature a low profile mushroom head style and work in concrete, block and brick. Not recommended for overhead applications. Specs: Drill Size - 3/16 inch; Max. Fixture Thickness - 1/4 inch; Min. Embedment - 5/8 inch; Min. Hole Depth - 1-1/8 inch.