Great gearbox
I mean... It's a Cyma gearbox, of course it's great! Shimming and grease out of the box leaves a bit to be desired as usual from any manufacturer, but you're going to re-shim and re-grease anyway, so that's fine. Gears are 18:1 and of good quality. Piston is 15 tooth, nothing special. Air seal is nice out of the box. The motor is alright, just your standard low-cost motor. The mosfet inside is great, but the trigger contact on the mosfet is on the fragile side at around 2mm wide and 4mm long, it pivots on a tiny pin, so be careful when pulling the trigger.