Red Head Multi-Set Drop-In Anchor 1/4 Inch feature an internally threaded, all-steel shell with expansion cone insert and flush embedment lip for anchoring into concrete. These Red Head anchors are manufactured from zinc-plated carbon steel, and should be installed with carbide tipped hammer drill bits. The lipped anchor body keeps the anchor flush at the surface, keeping all the rods the same length. These anchors allow for easy installation and easy inspection. The Multi-Set anchors feature expander slots that allow for easy setting and superior performance and a cone insert that expands the anchor when driven with setting tool and hammer. These drop-in anchors are typically used for solid concrete or lightweight fill decks. Specs: Corrosion Resistance Level - low; Bolt Size - 1/4 inch; Threads per Inch - 20; Drill Bit Diameter - 3/8 inch; Thread Depth - 3/8 inch; Embedment Min. Hole Depth - 1 inch.