Use Product Options Menu to Select Collet Size: 2.35mm (3/32") (H.MH-170) or 1/8" (H.MH-17018).

H.MH-170 High Speed Rotary Handpiece has a slender, contoured grip for precise and very high speed work up to 38,000 rpm. It has a fan cooled, brush-type continuous duty motor that runs cool and vibration free with permanently lubricated, shielded ball bearings that require no lubrication. 
It comes with a 2.35mm (3/32") or 1/8" collet that is easy to install and change with supplied collet changing wrench. Bur changes are quick and easy with a simple twist of the front section of the handpiece. A selection of collet adapters is available for simplifying changes between accessories with different shank sizes.
Comes supplied in Kits K.1070 and K.1090, and Dual Handpiece Kit K.1054. 
Also works with the same HP4-917 Control Unit that comes with Micromotor Kits K.1020 and K.1080.
Specifications:
6.2" overall length, 5/8" grip diameter, 1" motor diameter, 7.3 oz./208 gr., DC30V/1.2A. CE