12 Pc R8 Collet Set Metric 3mm to 22 mm High Precsion for Bridgeport 12 Piece Our Part # ALL-41056 High precision 12 piece set includes 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20 and 22mm R8 collets Made of high grade tool steel. Hardened and precision ground. Threaded internally 7/16"-20 Guaranteed T.I.R. 0.0005"