From: http://www.qingonggroup.com/products/112-.html

Adjustable Z Axis Spindle Mount Holder for CNC Router

Model: spindle diameter 100mm/85mm/80mm/65mm

This mounting kit is an adjustable spindle holder for cnc router, especially multi heads cnc router. This adjustable spindle holder is also called tool calibration, great for multi heads cnc router processing on different thickness work piece. It is easy to adjust the spindle station by this adjust z axis spindle mount holder to keep the cutter bits on the surface of the work piece, then do the same job. Save time to adjust spindle heads height.
Also good for multiheads cnc router machine working on same thickness material, it is easy to adjust and keep all cutter bits at the same level.

Features:
Material: Stainless steel and Aluminium
Diameter: 100mm (85mm/80mm/65mm, optional)

Payment can be made by Western Union, Paypal, T/T.