@skyfaller@jawns.club the specific pump mentioned in that link: Trudsafe Powered Air Pump for Respirator ($110 each) I seem to recall FitTestMyPlanet testing the Trudsafe and finding it leaked with fit factor of about 5 (bad), I can't find the link. CriticalAerosol followed this up and found similar. https://xcancel.com/CriticalAerosol/status/1670544219738628096 I remember there were others trying to fix the Trudsafe leaks, I can't really search Xitter externally, and I don't know what developments may have happened since then. Either way, I feel obligated to mention possible limitations of the Trudsafe. The link evaluated CADR and SPL, but not fit factor, trusting that the pump wasn't leaking. I recall some people recommending the Ford PAPR instead, quite a jump in price, but again this is two/three years ago. Are people still scoring government surplus PAPR for pennies?