i use an empire timmy. i used to use a a-5 with e-grip and rear velocity ajuster
Easy to assemble
Quick velocity change
Can easily fall apart
Makes things easier. The main problem is that it fell apart once when i was playing woods ball and i had to dig through the leaves and such crap to find the back screw and the spring. The thing is that while firing since its a screw the kick can cause it to unscrew. So you have to watch it.
Don't buy it. It is to easy for it to fall apart or start lowering the velocity.