A year down the road into my new hobby of long range big bore air gunning . With 300 lbs of lead slung down range in my new learning curve. My yong heng air compressor finally failed. I'm going to rebuild it an see how that goes. I'm wanting like many of you a more reliable source of high pressure air. Booster pumps are amazing in principle and are easy to maintenance rebuild with longevity of life. Altaros makes a booster very friendly In price options and warranty and were very nice to answer my questions. Second is extreme big bore air rifles booster. I called them and they answered all my questions said lifetime warranty on major components Texas USA company. Comparable price to altaros. I have also.been checking into Haskell air driven gas boosters. They have been made since 1975 NASA airline industry and flammable gas. They will fill to.high pressure 5500 psi for new scba Scott 5.5 bottles. After talking to Haskell dealer receptionist and salesman they were very nice but couldn't answer my questions on there boosters. So they transferred me to there services department they were absolutely rude and did not want to be bothered writing quotes or answering questions. There units used refurbished are $3600 and up new $6600 and up. Long story short Haskell may be the best booster made . but I dnt ever want to deal with there service dept again. Chicken thief and many others have been using the altaros with excellent results. Does anyone have experience with extreme big bore booster?