1Double bearing structure can withstand high rotate speed and improve grinding efficiency as well. 2Free rotate speed can get to 65000RPM, and the good sealing also ensures safe and stable rotating. 3Comes with a long air hose, the lightweight and small air grinding pen allows for simple operation. 43mm collet promises the high accuracy in your grinding, suits for grinding, engraving, carving, etc. 5Designed to have a sturdy structure, this air grinder has excellent durability for long term use. Item Type: Pneumatic Grinding Pen Material: Alloy Steel Product Model: KP-6091 Free Speed: 65000rpm Collet Size: Approx. 3mm / 0.1in Working Pressure: 0.5-0.6MPA 1 x Connector 1 x Pneumatic Grinding Pen 2 x Wrench 1 x User Manual Before use, confirm whether the chuck is fixed to ensure that the air nozzle has no leakage.