1/2-inch-20 UNF to SDS max - The Chuck Adapter connects 1/2-inch-20 UNF chucks to SDS max hammers. It is compatible with rotary hammers. Features and Benefits • Connects 1/2-inch-20 UNF Chucks to SDS max Hammers • Chuck Adapter connects 1/2-inch-20 UNF chucks to SDS max hammers • Compatible with rotary hammers Specifications Shank: SDS max For drill bit shank: 1/2"-20 UNF