4.0Mm Min Bore Guhring Boring/Profiling Lh System 104 Insert, .015Mm (T-Max) Offset, 27Mm Reach, Nano-A Coated Left Hand, 0.25Mm Radius, Tialn Coated Gt104.0837.025.27.40.L, Nano-A Coated Type Gt104 Guhring Micro-Precision System 104 Carbide Stick Insert With 4Mm Quick Change Shank For Boring & Profiling. Guhring Series No. 25085 Order Code 4.026 Made In Germany, Guhring Part #9250850040260 Guhring Inc.