get the one from Demon paintball - as Tony the Tiger would say "they're grrrreat"! (and cheap, I imported mine from the states a few months before they started selling over here cost a lot more than £2.50), another alternative is to hacksaw the feed neck and the bit above it where the screws are on a normal 200 shot hopper, cut a hole a little smaller in a chewing gum pot, apply lots of insulation tape and bingo - 50 shot hopper.