The box says its Tokyo marui for M4's but wasn't sure if it was compatible with other brand M4's
Flex - nothings wrong with either gearboxes, the TM box is front wired as that's where I have battery's so I didn't need to buy anymore, I'm fitting a MOSFET (when it arrives) I can disassemble the TM box, see how its all done and solder in the MOSFET, put in my rifle and keep the other as a spare
Simple fact is, its an experiment, for £50 I think its good as most are £60+