This Wera 784 B Metal 3/8"" Square Drive-1/4"" Hex Screwdriver Bit Adaptor Chuck is a high-quality tool from Wera Tools. It is designed to be rugged, reliable, and reasonably priced. This adapter converts a 3/8 inch square drive to a 1/4 inch hex quick-release chuck. The product code is 042755 and the model number is 784B/1.