ER40 wrenches can be used to tighten ER40 collet nuts on CNC machines and other equipment 

Wrench usually made one or both ends of the handle opening or aperture sets of clamping bolts or nuts.

Wrenches are made in various shapes and sizes and are used for gripping, fastening, turning, tightening and loosening things like pipes, pipe fittings, nuts and bolts.

ER16M Wrench suitable for the nuts removal of ER16M type cutter bar, cutter handle and extension rod. ER wrench features: simple operation, low price, high labor intensity.