Unless rubbing your nipples is part of your job, anyway.. Andractim testosterone gel is a topical gel, which comes in a tube, containing 80x 25mg doses of DHT. Absorption rate is going to be similar to testosterone gel, or roughly 10%, so youre applying 2.5mgs of pure DHT to your nips every time you use this stuff.
Servos are also used in in-line manufacturing, where high repetition yet precise work is necessary. Of course, you don't have to know how a servo works to use one, but as with most electronics, the more you understand, the more doors open for expanded projects and projects' capabilities.
Servos are constructed from three basic pieces; a motor, a potentiometer (variable resistor) that is connected to the output shaft, and a control board. The potentiometer allows the control circuitry to monitor the current angle of the servo motor. The motor, through a series of gears, turns the output shaft and the potentiometer simultaneously.