Excellent jig - clever and well made with high quality components.One sliding positioner works with both 2-1/4 and 2-1/8 Forstner bits via nylon reducer/positioner bushings.Other size sliding positioners are available for 35mm, 55mm and 68mm Forstner bits.My only quibble - the same I have with other True Position jig sets - is that they come in a fitted cardboard box.At $399 for the set - a plastic case would be nice.