ASTKilo23 does a complete review of the ASTKilo23 On The Arcturus AK12 PE gearbox which includes a comparison with the first generaion Arcturus AK12 AEG gearbox... "Arcturus has been making a wave in the Airsoft world with their latest released. The PE model of their AK gearbox is no exception. With quality parts and a range of awesome upgrades, it is a drop in gearbox for many AKs (not just Arcturus) that will instantly boost the performance and features of your AEG. It is currently available and many retailers and quite impressive. In this video I compare it to the 1st generation Arcturus AK12 gearbox, which used a microswitch and was far less compatible with regular TM standard parts. This new PE model returns to the tradition of having a mostly TM standardized spec, allowing for other upgrades and replacement parts to be used."