Self-contained and simple to install the Aircraft Mechanic 22 -33cc size electric main retract units take their power from your receiver battery and, for aircraft with a tricycle undercarriage configuration, work in unison with the Aircraft Mechanic 22 - 33 size nose retract unit (4406355). Beautifully machined, sturdy and slop-free the mechanism rivals some of the best examples on the market at a price that doesn't break the bank. Kiss goodbye to troublesome air and mechanical systems and enjoy solid, dependable performance, time after time.