Cuts receiver thread minor diameter for the Piloted Tap/Mandrel. Cuts receiver lugs to equal heights. Must use with the Receiver Tap Bushings which are included with Manson Receiver Taps sold here. Available Standard or .010" Oversize. Mfg: Manson Precision SPECS: High speed steel. 10A 1/2" (26.6cm) long. .010" Over -1.012"diameter; Standard - 1" diameter.