Its really for 11.1v lipos that a mosfet becomes essential. It doesnt hurt to have one in any gun though. Dont run an 11.1v lipo they are just pointless more for the penis measurers than anything. Only a few people ever set their gun up properly to get the real benefit without it damaging the gun. Use a 7.4v 20c+ lipo its plenty for the real world, at the the end of the day the only shot that counts is the one that hits no need for 25rps.