ITEM NAME:6mm to 3.175mm 1/8" Engraving Bit CNC Router Tool Adapter for 6mm Collet LJ Material : Spring steel Function : Engraving bit CNC router tool Adapter 6mm to 3.175mm 1/8" Size Dia. (Outer): 6mm ,Dia. (Inner): 3.175mm(+/-0.1mm) Length: 24mm Package Included: 1 pcs CNC router tool Adapter Material : Spring steel Function : Engraving bit CNC router tool Adapter 6mm to 3.175mm 1/8" Size Dia. (Outer): 6mm ,Dia. (Inner): 3.175mm(+/-0.1mm) Length: 24mm Package Included: 1 pcs CNC router tool Adapter.Size Dia. (Outer): 6mm ,Dia. (Inner): 3.175mm(+/-0.1mm).