Ryobi A10MK21 3-in-1 1/2 Inch Multi-Chuck Keys for Ryobi Drill / Drivers WORKS WITH MOST 1/2 CHUCKS THREE PILOTS: 9/32 inch, 7/32 inch, 1/4 inch CENTER HOLE built into the key so you can hook this up to a lanyard or carabiner DURABLE METAL CONSTRUCTION for optimized durability SPECS: .75 Depth, 2.5 Height, 2.75 Width