Description: These bit holder and extension adapters are made from high quality carbon steel and chromium-vanadium steel with heavy duty construction to ensure maximum durability. It can be used for drills and bits making these extension adapters very handy and multipurpose. Features: Hard steel adapter for maximum durability, the heavy-duty construction allows for long service life.Ball detent design for quick connect or disconnect and ensuring stay in place while driving. Universal SDS plus shank would fit many electric drills and chuck. The small size allows you to bring your bit extension anywhere to get any job done and can fit into many tool bag. There are one hex socket and three square adapters in different sizes and you can use the proper one for various needs.Specifications: Material: Stainless steel and chromium-vanadium steel Type: SDS Plus--80mm x 1/4" hex socket, SDS Plus--65mm x 1/4" square head, SDS Plus--65mm x 3/8" square head, SDS Plus--75mm x 1/2" square headQuantity: 4 Package Includes: 1 x Hex Socket Extension Adapter3 x Square Extension Adapters.