Made of High Quality Tool Steel , this is a high quality tailstock die holder for threading, tapping and reaming operation on your lathe machine* Imperial dies size holding capacity - 13/16", 1" & 1-1/2" Inches * Tap holding capacity of the 2 tap wrenches supplied along are : 1/16" to 1/4" (M2 to M6) & 1/4" to 1/2" (M6 to M12) Inches * Chose from the option of the shank sizes of MT1 , MT2 and MT3 Shank, that goes inisde your lathe tailstock & intended job for threading / tapping is hold in rotating chuck. * The Die for threading purpose is hold in the various Die holder sizes. The internal bore threading/ tapping is done by mounting the tap wrench head as per tap size between the above advised range is moved toward the rotating job in the lathe's chuck.