Miniature laser aligning system for 050 Flat and 187 Round Nozzles. The laser fits into the end of the nozzle and indicates where the center of the jet will hit the grinding wheel. The nozzle adapter it comes with fits standard nozzle apertures. The laser unit uses internal battery cells which are commonly available. Laser system comes with the flat and round nozzle adapters. The nozzle must be purchased separately.