Product description The correct methods of mounting the collet nut: 1. Put the chuck into the pressure cap, gently turn the clamp spring, when eccentric portion of the pressure cap recessed clamp spring groove. Along the arrow direction and use equal force to push clamp spring, can mount pressure cap. 2. Put the clamp spring and cap all together installed on the chuck body or spindle. Insert into the clamping hole after wipe the cylindrical shank, use a wrench to tighten the pressure cap, until clip firmly the tool before use. (Note : Avoid fastening pressure cap that not installed tool, to avoid damage the clamp spring) 3. Use a wrench to loosen the pressure cap and took out the chuck or tool, remove the tool. Along the direction of the arrow push out the clamp spring. Then according to need replace other clamp spring. Specification: Color/Style: ER20 Material: High Grade 65Mn spring steel Total height: 31.5mm/1.24inch Outer diameter(Max): 21mm/0.83inch Run-Out Tolerance: <0.008mm Gripping Range: 1MM to 13MM (1mm,2mm,3mm,4mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm,13mm) Fits metric shank size(s): For example,1mm Collet Fits 1mm metric shank,2mm Collet Fits 2mm metric shank Package Includes: 1 Set(13pcs) x ER20 Collets .