It is ER25 Exactness spring collet. Widely used in boring, milling, drilling, tapping, cnc, sculpture and other processing operations, also can be supported used with the holder of cnc tool.

Specification:
Color/Style: ER25
Material: High Grade 65Mn spring steel
Accuracy : 0.01mm
Run-Out Tolerance: 0.015mm (0.0006")
Gripping Range: 2MM to 16MM (2mm,3mm,4mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm,13mm,14mm,15mm,16mm)
Fits metric shank size(s): For example,1mm Collet Fits 1mm metric shank,2mm Collet Fits 2mm metric shank

Package Includes:
15 pcs ER25 Spring Collet (2mm,3mm,4mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm,13mm,14mm,15mm,16mm)

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 Coverrecessed clamp spring groove. Along the arrowdirection and use equal force to push clamp spring, can mount pressure cap.
2.Put the clamp spring and Coverall together installed on the chuck body or spindle. Insert into the clamping hole after wipe the cylindrical shank, use a wrench totighten the pressure cap, until clip firmly the tool before use.
(note: avoid fastening pressure Coverthat not installed tool, to avoid damage the clamp spring)
3.Use a wrench to loosen the pressure Coverand 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.