Hitachi 724934 SDS Max 5-Inch x 11-3/8-Inch One Piece Hollow Core Bit Hollow core bit measures 5-inches in diameter and 11-3/8-inches in length Roof-shaped guide teeth (1) ensure improved tool alignment and increased rotational stability Flat hammer teeth (2) are significantly more efficient in this drilling base Hammer hollow core bit is specially suited for modern, powerful rotary hammers Comes with a 30-day limited warranty Roof Shaped Guide Teeth Flat Hammer Teeth Increased Durability Performance Increase Exceeding 30%