Er11 Collet Set: Er11 collet has a height of about 18mm / 0.7inch, an outer diameter of about 10mm / 0.39inch, and a runout tolerance of 0.015mm. Spring collet chuck set has 15 different sizes for a range of applications Spring Steel Material: er11 collet set is made of 65Mn spring steel material, fine workmanship, good elasticity and high precision. Our cnc spindle collet set is used for CNC milling lathe tools and workpiece clamping engraving machine Hand Engraved Marking: The router collet kit has hand engraved size markings, you can easy to identify and store the tapping machine collets, also easy to distinguish the size of the workholding collet tools when using them. With Storage Box: Each spring collet has a yellow storage box, which is marked with the size and type of the collet. The storage box of the independently packaged CNC spindle collet can be carried individually when needed, and it does not take up space in the tool box These spring collets are made of 65Mn spring steel for CNC milling lathe tool and work-holding engraving machine. There are total 15 collets of sizes in on set which can basic meet your need. Collet must be placed into collet chuck nut before inserting into collet chuck. Each collet is well packed in separate protective container with label. For CNC milling lathe tool and work-holding engraving machine. 15 Different Sizes: The router collet set includes 15 different sizes: 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 1/8inch, 1/4inch. Please confirm whether the size is suitable before purchasing the spring collet set Colour:As Shown Material:Metal Package Contents: 15PCS x ER11 Collet Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.