Drive spindle extensions allow shanks of grinding and milling tools to be extended. They allow access to hard-to-reach areas and are clamped into the collet of the machine (air or electric grinder) or into the flexible shaft handpiece. Drive spindle extensions are a cost-effective alternative to special made-to-order burs and mounted points with long shanks. Extension for drive spindles with a working length of approx. 50 mm, a tool mounting of 1/8" and a shank holder of 1/4"." Recommended extension for drives with a maximum rotational speed of 44,000 RPM. 2 keys DM SW 6/7 mm and 1 collet 1/8".