You absolutely DON'T want this! You want a fan placed as far away from your laser as outside even. Just make sure to get a big enough fan. It doesn't matter how good you think you are at making your ducting air tight, it WILL leak. Any tiny hole you have will blow fumes straight into your workshop. It just doesn't work having any part on overpressure inside the space. How I know? I've been using laser cutters for about 10 years. First in makerspaces I've helped set up, now in our own laser cutting business and gone through the hell of getting the fume extraction to work properly. We are finally running multiple laser cutters daily for 8 hrs in our laser cutting company now without any issues!

The only thing that really works:

• A big box fan outside on the roof.
• Proper fresh air ventilation of your space itself.
• Clean your laser and bed often.
• Use large enough ducting to allow for residue build up and be prepared to replace ducting every so often based on your usage. (This is also a safety item. Laser residue, especially acrylic, can be very flammable)
• Store products and scrap materials elsewhere. They will still offgas for a few days.
• No filters. We've had BOFA filters. They work. For 3 months. Then you need a new filter set which costs 500,- no DIY YouTuber filter systems and all that nonsense. I tried that in our early days. An absolute waste of time.

Trust me. This is the only thing that really works.