Description : High precision milling cutter woodworking collet chuck . Carbon steel material , flexibility and wear resistance . , tight and stable clamping , improve work efficiency . for engraving machine , trimming machine , perfect woodworking tools . Suitable for manufacturing , mold manufacturing , machinery manufacturing on . Specification : Material : Carbon Steel Color : Black / Silver AR - 6 / AR - 8 / AR - 6 . 35 : Big head diameter outside : 7 / 16 & 39 ;& 39 ; ( 11 . 1mm ) Small head diameter : 11 / 32 & 39 ;& 39 ; ( 8 . 8mm ) Length : & 39 ;& 39 ; ( 8 . 4mm ); 35 / 128 & 39 ;& 39 ; ( 6 . 9mm ); 11 / 32 & 39 ;& 39 ; ( 8 . 6mm ) Hole diameter : 6mm ; 8mm ; 1 / 4 & 39 ;& 39 ; ( 6 . 35mm ) Package Includes : 3 x Chuck Head Note : Please 1 - 3mm error due to manual measurement , sure not before . Due to the different monitor effect , the actual color may be slightly different from the picture color .