It's a home-brew, I can put up the STL later today or tomorrow if interested. The design requires (4) M2x8 countersunk screws and nuts. Optionally (8) 10mm did x 3mm magnets, https://www.amazon.com/gp/product/B07842PSJD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1, if you want magnets in the base. I'd like something with a little more sticking power so it may change in the future.
I really like the Pit Viper fan, super clean install through a base vent with the separate Weber adapter: https://bbqguru.com/storenav/Index?categoryId=&&productId=403
I have all the other bottom vent holes plugged up with 3/4” plugs: https://smile.amazon.com/dp/B00MN6GEC2/ref=cm_sw_r_cp_api_glt_fabc_MZXAY7Y1PXD1Z1516Q8A?_encoding=UTF8&psc=1
Found both of these thanks to comments on here and other forums. Really love the setup, no fiddly tape and no bulky adapters. Works great with the Fireboard.
That's probably the problem. What kind of smoker do you have? You might try sticking some lava lock around the lid and other doors, to get a better seal.