Call anyone hoping to only use 1 of 6 Solder Fume Extraction. It doesn't work with just one. The smoke was reduced by about half. So two can work. However, if you want to be sure the smoke doesn't get through, hold it up to a light. With the way I see the light (simply by pointing it at the ceiling light from the floor). 1, you can see the light through it. .2, the light is worse to see 3, almost correct 4, almost no light to see 5, I can no longer see the ceiling fan light You can add a 6 to protect more from soldering fumes. In other words, if you're looking for a 6-filter bargain (which sounds great), think again. You pay more or less only $12 for a filter. If that suits you, then go for it!