Use Product Options Menu to Select Collet Size: 2.35mm (3/32") H.MH-130 or 1/8" H.MH-13018.

H.MH-130 Portable Rotary Handpiece (motor) is small and lightweight yet has plenty of power for fine detailing, polishing and even grinding on metal, wood, glass and many other materials. Its fan cooled, brush type continuous duty motor runs cool and vibration-free. It has permanently lubricated, shielded ball bearings that require no additional lubrication. 
The handpiece 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. This handpiece comes supplied in Kits K.1030 and K.103018.
Also works with the same HP4-310 Control Unit that comes with Micromotor Kits K.1030 and K.103018.
Specifications:
5" overall length, 1/2" grip diameter, 7/8" motor diameter, 6.46 oz/183g, DC12V/1.2A, 4.11in.-oz or 29mNm or 25W Max Torque or Watt Output 
Cord Length: 59"