I also have an inline booster fan. I opted for one of the dryer booster fans. Metal construction and operates on standard line voltage. Didn't bother with auto-turn on, but I do have it on a HomeKit outlet (Hey Siri, Turn on laser fan!).

No matter what fan you get make sure the housing is sealed. A lot of the 4" fans are designed for uses that don't require a 100% seal. I used gaffers/duct tape to entirely seal the fan body as there were significant leaks.

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