Description: This adapter can be attached to a ratchet, etc. to a 1/2 inch (12.7 mm) insertion angle to a 3/4 inch (19.1 mm) DR. Knurling for slip resistance Product Specifications: Drive: 1/2 inch DR (12.7 mm) to 3/4 inch DR (19.1 mm) Material: Chrome vanadium Surface Treatment: Mirror & Knurling