Quality Alloy Steel Tap Extensions Walton's Style B Tap Extensions can be used for both machine and hand tapping in hard to reach areas. These quality alloy steel tools are heat-treated and each Tap Extension fits an individual tap size, and square or round sockets conform to the size standards of numerous tap manufacturers. The deep socket of the extension supports the tap, which I held firmly in place by 2 socket set screws that are 90 degrees apart on the square of the tap. The Style B Tap Extensions are available in various sizes, fitting metric taps from 1.6mm to 38mm or #0- 1 +". The Extensions can also be purchased in a set of 9, fitting 15 tap sizes from 1.6mm to 12mm and #0-1/2". 3 hex keys and 6 extra socket set screws are included in the set's sturdy plastic case.