In view of the comments on the JR3421s I am putting mine on long tern test on 4.8 volts, I'll report back on any problems. On my BobCat I use the JR 9411s, on rudders, fit perfectly, work perfectly, more torque than the 3421s I bought the 3421s only last November and with over 150 JR servos bought in the last 20 years I have not had a single failure, quite a record.