Features:_x000D__x000D_Engraving Bit CNC Router Tool Adapter after heat treatment and precision grinding,fine grinding,concerted and high precision size; suitable for engraving machine ER collet. _x000D_Quality steel production,heat treatment, has good flexibility and abrasion resistance. _x000D_Clamping force, high accuracy, good gripping stability. _x000D_Commonly used in the engraving machine spindle motor folder knife, with the engraving machine collets use. _x000D__x000D_Specification:_x000D_Material: Steel_x000D_Size OD to ID(mm): 6?3.175_x000D__x000D_Package include:_x000D_1 x Engraving Bit CNC Router Tool Adapter 1Engraving Bit CNC Router Tool Adapter after heat treatment and accurate grinding,fine grinding,concerted and high accurate size; suitable for engraving machine ER collet. 2Quality steel production,heat treatment, has good flexibility and abrasion resistance. 3Clamping force, high accuracy, good gripping stability. 4Commonly used in the engraving machine spindle motor folder knife, with the engraving machine collets use. 5Engraving adapter is processed with accurate grinding, with great clamping force, high accuracy, and good gripping stability.