4.0Mm Min Bore Guhring Boring/Profiling Lh System 104 Insert, 0.60Mm (T-Max) Offset, 17Mm Reach, Uncoated Left Hand, 0.15Mm Radius, Bright Uncoated Gt104.4737.015.17.40.L, Uncoated Type Gt104 Guhring Micro-Precision System 104 Carbide Stick Insert With 4Mm Quick Change Shank For Boring & Profiling. Guhring Series No. 25073 Order Code 4.031 Made In Germany, Guhring Part #9250730040310 Guhring Inc.