This Is the one upgrade any cocker owner must buy. Every cocker lover must have one of his markers E2'd. This product was a vast improvment over the e1, the batterylife was increased, the solinoid was fully encasted, and the preformance was upgraded. with proper settings and marker exessories ( RAM QEV's ect) It is possible to see Rates of fire in excess of 20bps. This model offers several modes, COFA, PSP, MILL. SEMI TRAINING, those i remmeber off the top of my head. Differences in the modes are trival, most notably is the ROF that the ranmping kicks in. The display also offers a ROF indicator, but has the option for a game timer. This was pretty pricey a few years ago, but now if you can find one, they can be fairly cheap. Again, This is a MUST have upgrade on atleast one of your cockers. I swear by mine.
The End all Be all cocker upgrade. From here you can worry about supplements, Rams, LPRs, Valve kits, ect. But get the e2 frist.