Brass SpareAir adapter for filling your spare air bottle directly from your scuba tank=used very little,always kept clean and dry and works as it should.The spare air tank and regulator will need hydro and re-seal.The tank/regulator has sat for 4 or 5 years and stayed full for several years but is empty now so it will probably need some attention before you could use it.I'm old and don't dive anymore so I don't have a big tank to test it with.Selling as is! Shipping to 48 states.I may have to unscrew regulator from tank to ship.