go to central hobbies.com.buy the maverick starter.its the one for 79.95 i beleive.buy the extra cone for gas engines.my total bill with shipping for all mentioned was 109.00 shipped and it came with 2 batteries.these batteries are the same ones the cars use.7.2 volts each.i put it on my us 41,i didnt slam it on while spinning.i just put on the cone and pressed button and the engine spun over fast and fired on the 3rd or 4th revolution with no problem at all.it is claimed it will start up to a g-62 no problem and i dont doubt it the way it started mine.it uses 2 bats,2 motors,then there reduced to one drive.