Wera Female Square 784 B/1 Quick-Release Chuck, Adaptor 1/4" x 3/8" Drive
Wera Adaptors for 1/4" and 5/16" hexagon insert bits and Wera series 1 and 2, features the quick release chuck for a firm, wobble-free connection that can be released quickly. Conversion from female square drive to a hexagon bit. Wera – The Best Tools For The Job!