This 0.5-3mm twist drill chuck set is made of copper with excellent workmanship.(Please get the promo code on the product page when purchasing to get a more favorable price.) 14pcs Collet chuck set：2 set collet（0.5mm, 1.0mm, 1.5mm, 2.5mm, 3.0mm);2pcs Copper drill file;2pcs Axle(2.35mm,3.17mm); 2pcs Hex Key Copper material can be stable and durable, good micro electric drill accessories Collets can be used with twist drill as mini hand drill for ABS board, aluminum shet, cardboard drilling. For small drill, and after connecting with motor for PCB boards, drilling to make special mini drill Feature: 2.35mm and 3.17mm two kinds of copper drill file in one package Drill collet: 0.5mm, 1.0mm, 1.5mm, 2.5mm, 3.0mm This 0.5-3mm twist drill chuck set is made of copper with excellent workmanship. Can go with twist drill as mini hand drill for ABS board, aluminum shet, cardboard drilling. Easy to ABS board, wood, aluminum sheet, cardboard punch Specification: Material: copper Color: golden