@Texan_Reverend@kind.social They are available. But: IKEA filters are 45 $currency each (at 16x10") Computer fans are 30+ each, or a single fan with good suction is around 200 Xiaomi purifiers start at around 300-400. It's nice to be able to create those things yourself. Unfortunately from my calculations for this location price comparison doesn't come out that favourably unless you're doing a lot of units, at which point it's a lot of effort.