<b>SPTA RT388AC Advanced Multi-functional Rotary Tool Kit With 388Pcs Rotary Tools Accessories</b><br> <br> <b>►Carbon Brush:</b> Play the role of electrical conduction by friction with motor to produce spark, which prolong the service of life of the motor; <br>According to normal working principle, the carbon brush will wear out, and the motor would stop working after run out of carbon, so it should be replaced regularly.<br> <b>►Speed Controller</b> Adjust 6 dials of variable speed freely, meeting your different needs for smart adjustment of output power when operating.<br> <b>►Copper Cores</b> It is in good conductivity, could reduce resistance and maintain a good working temperature, to extend the motor life.<br> <b>►Stator</b> High-quality thickened silicon steel sheet for impact resistance, stable and quiet operation.<br> <b>►Capacitance</b>Protecting the motor during start-up and overload.<br> <b>►Rotor</b> After dynamic balancing test, the stability of high speed operation is improved.<br> <b>►Ball Bearing</b> High-performance bearings provide high-speed operation stability and service of life.<br> <br> <b>Installation of Bits on Flex Shaft:</b><br> 1.Remove the shaft collar.<br> 2.Loosen the collet nut.<br> 3.Raise the handle end of the flexible shaft & shake gently until the inner flexible shaft protrudes from the fitting collar.<br> 4.Insert the inner flexible shaft into the collet then tighten the collet nut.<br> 5.Screw the flexible shaft fitting collar onto the rotary tool.<br> 6.Insert the hex key into the hole on the handle.<br> 7.Loosen collet nut then insert shank of accessory into collet.<br> 8.Tighten collet nut by included allen wrench and check all fittings to ensure they are securely fastened.<br>