Craftsman 6 Inch Extension Bar, 1/2 Inch Drive, 9-44131 The drive size of this extension is 1/2" and it will fit all 1/2" ratchets Extension allows you to get up 6" more depth when trying to reach nuts and bolts Extension size is stamped into the top of the extension so you can find the tool you need easily Helps prevents injuries to knuckles and eliminate the need to completely disassemble projects to reach tight spaces Backed by Craftsman's Lifetime Guarantee