Manufactured from high speed tool steel, these cutters replace the cutters that came with your Sinclair Neck Turning Tool, in the very rare case that you wear one out. 30Adeg cutter is a direct replacement to the cutter provided with your Sinclair Neck Turning Tool and a 40Adeg cutter is also available for turning necks on Improved cartridges. Fits all Sinclair Neck Turning Tools. Mfg: Sinclair International