Amazon.com : Quick Release 1/2-Inch Square Drive to 1/4-Inch Hex Female Socket Impact Adapter Drill Chuck Set of 2 for Air and Electric Impact Wrench : Patio, Lawn & Garden
Bestgle 1/2-20UNF Mount 1.5-13mm Capacity Key Drill Chuck for Air Impact Wrench Converter Conversion Tool with Chuck Key and 1/2 inch Socket Square Female Adapter - - Amazon.com
DEWALT Chuck in the Drill Parts & Attachments department at Lowes.com