4.0Mm Min Bore Guhring Back-Bore/Profile Lh System 104 Insert, 1.00Mm (T-Max) Offset, 32Mm Reach, Nano-A Coated Left Hand, 0.10Mm Radius, Tialn Coated Gt104.3237.010.32.40.L, Nano-A Coated Type Gt104 Guhring Micro-Precision System 104 Carbide Stick Insert With 4Mm Quick Change Shank For Back Boring & Profiling. Guhring Series No. 25109 Order Code 4.017 Made In Germany, Guhring Part #9251090040170 Guhring Inc.