Hilti 5/16 in. x 2-1/2 in. Coarse Zinc-Plated Steel Hex-Nut-Head Sleeve Anchors (5-Pack) are suitable for medium-duty fastening jobs in block, masonry and concrete base materials. The stud-type anchor design provides easy, dependable through-type fastening and can be set in bottomless holes. Anchor size is the same as the drill bit size.