Main functions and controls of BLTouch are same as usual auto bed leveling sensor, consists of RC servo and micro switch. Thus, BLTouch can be applied on almost every board. BLTouch fulfilled simple structure and high precision by using progressively designed solenoid and hall sensor, and aimed user convenience and enjoyable printing by adding many smart functions, self-test, alarm, alarm release, test mode for M119. - Simple BLTouch can be easily applied, since it has a small and simple structure. - Smart [Self-test]: The push pin is operated three times to test when the power is on [Alarm]: The LED light blinks if a problem found on a self-test or on an operation - High-precision BLTouch's Standard Deviation in repeatability is around 0.005mm, at that precise. Includes 1 Meter extension cable set.