★ Specifications - Air Micro Grinder Pneumatic Grinding Machine Air Inlet: 1/4 inch, 1/8" Collet. Average Air Consumption: 90 psi. No-Load Speed: 65,000 rpm. Working Pressure: 6-7 map. Recommended Tracheal Diameter: Approx. 8 mm. Package Contents: 1pc x Micro Grinder. 1pc x 44.5 inch Hose. 2pcs x Chuck Keys. 1pc x Coupler. 1pc x Manual. ★ Features - The mini air pencil grinder is made of solid metal material, wear-resistant and practical. Free speed, small size and light weight, lightweight pen-shaped design, easy to hold and operate, high strength, flexible, safe to use and can be used for a long time. ★ Compact Power - This mini straight pneumatic die grinder glides across surfaces with a speed 65,000 RPM free air flow and 90 PSI working air pressure in conjunction with an air compressor. Small in size and lightweight, the pen-shaped design is easy to operate with one hand. ★ Widely Used - The pneumatic pencil grinder can be used in various fields of metal cleaning, chamfering,