Hydro Air #8. These are good old school dumps that are precise and can still be used. They can typically be purchased in the neighborhood of $100-325 each, depending on the demand and quality of the part. The only disadvantage about this dump is that the bodies can crack when they are being used roughly. These are not ideal for hopping, for that, you should use newer pump heads. These dumps are also without a pressure release, which is used to reset the dump from over locking.