Like new 2.5 lb aluminum CO2 tank. I bought this to be my backup but I've since put together a paintball tank system that I can use for that. It's been filled and emptied exactly twice. Standard right-hand CO2 threads, will work with any normal regulator. Asking $35 plus shipping, which should be about $13 in the Lower 48. If you want an exact shipping quote just PM me with your ZIP.