Slr upgrade parts compatibility

hi quick q, just wondering if slr needs specific ‘slr’ spring retainer or if something like a gen9 would fit.

also which metal triggers can fit slr? does it need a specific one?

Gday, I’m pretty sure you need parts to suit the v2 style boxes, I’ve tried alloy triggers that didn’t fit but went straight in my acr, when buying stuff just make sure it says SLR compatible. I found the only cylinder head that actually fits snug in the gearbox is the standard nylon one, I have several alloy twin oring that say SLR but don’t really fit well.
But a lot of knock off parts are hit and miss.