This is the Futaba Micro Fail Safe Unit. *** THIS IS NOT INTENDED FOR AIRPLANES OR HELIS, THIS IS FOR CARS, TRUCKS, OR BOATS DUE TO THE LOW CUT OFF POINT. ****** Prevents runaway R/C vehicles by automatically returning throttle servo to preprogrammed setting in the event of interference or low battery voltage Works with any scale R/C car or truck 4.8V (4-cell) or 6V (5-cell) NiCd receiver batteries, see COMMENTS One button programming and status LED One Futaba Micro Fail Safe Unit Connecting between receiver and throttle servo Length: .85" (21.5mm) Width: .6" (15.5mm) Height: .3" (7.5mm) Weight: .18oz (5g) For use with NiCd batteries only, no alkalines or Manganese dry cells. The Discharge curve of alkalines and NiMH cells is different from that of the NiCd cells for which this unit was designed. Non-NiCd cells will not provide the warning at the appropriate time. Does not work with transmitter in PCM mode Works with the 2.4 GHz in PPM mode. jxs 5/19/05 ir/kh updated jpg 3/30/06 updated jpg 10/12/08 &