It is a Cyma v2 gearbox exactly same type used in cheapy CM513's etc....
The gearbox is re-enforced at rear so needs a little modding to fit in 13:1 or 12:1 sets
(the spur hits the arc, so needs to be modded to remove a small arc so that spur clears)
It is a v2 but uses a v3 spring guide in there ???
Also the tappet plate has some cut outs up front where the box is re-enforced at front
(similar to a Lonex tappet plate, can use a SHS tappet with some modding)
(Clear tappet plate is a bit loose on red SHS nozzles - try the new black SHS nozzles with plastic lug in center or replac
