I just found unused Drager tanks still in the mfg box but the date is 2008 and they haven't ever been Hydrotested. They say that they are unused so they're probably really good tanks for filling yourself.https://www.ebay.com/itm/Drager-4500psi-SCBA-tank-45-minute-carbon-wrapped-Unused-2008-mfg-date-65-5-SCF/231312000514?hash=item35db450602:g:pd4AAOxyhS9Th9oo:rk:32:pf:0You could also get them Hydrotested and be good til 2023 if you wanted to get them filled at a dive shop. Getting them hydrotested cost's about $25
So i am browsing around on Aliexpress looking at different sellers for an air pump and i found this https://www.aliexpress.com/item/6-8L-carbon-fiber-SCBA-air-tank-bottle-cylinder-300-bar-4500-psi-for-breathing-or/32797724875.htmlThoughts?