The Ray Allen trim servo is designed specifically for experimental aircraft. They are small, lightweight, and powerful enough to control trim surfaces on any small aircraft. They will automatically stop when their travel limit is reached and will not travel unless power is switched on by the pilot. Voltage polarity determines direction of travel. They are extremely durable and should last the service life of your aircraft. Production samples have been bench tested 50,000 cycles under loaded conditions relating to 244 hours of continuous use or thousands of flight hours.