I still have 6 of them and the radio they came with. I purchased the JrPCM 9 new from Circus Circus. I don't use the trans anymore although it still looks/works as new. The factory instruction book does not give any information on servos. I still use these servos occasionlly on small fun fly type aircraft. I sent my 4001s back to Horizon two years ago for service. New pigtails, pots and cleaning. I was told these servos had 50 oz of tork and were still very useable. I should retire mine as I have lots of 4031s, 4131s, 4721, and twelve of the 8321 and 8411 digitals. I hope the newer JR servos last as long and give as good service as the 4oo1s I have. LeRoy