Air Duct Adapter for DIY Humidifiers – 4-inch & 5-inch Output

Connect Round Ducting to Your Mist Maker Build

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The Air Duct Adapter makes it easy to connect standard round ducting to your DIY humidifier reservoir — a clean, secure output port for directing mist exactly where you need it. Route fog into a grow tent, mushroom fruiting chamber, greenhouse, or reptile enclosure without cutting rough holes and improvising seals.

✅ What It Does

• Creates a clean, round output port on your reservoir lid for standard flexible ducting

• Doubles as a fan intake adapter — connect your waterproof fan intake to outside air via ducting

• Slips through an X-cut in a Martha tent or grow-tent wall and holds in place

• Available in 4-inch (the most common size) and 5-inch to match your ducting

🔧 Installation Tips

Cut a hole the same diameter as the adapter in your reservoir lid or tent wall. For tent walls, cut an X and push the adapter through from the inside — the flange holds it in place. For rigid lids, the adapter sits flush and can be sealed with silicone caulk for an airtight fit.

Which Size?

For most builds, go with the 4-inch — it's the more common choice because standard 4-inch flexible duct is the easiest and cheapest to find at any hardware store, so it connects right up with nothing special to track down. Step up to the 5-inch only when you're moving a lot of fog over a longer run and want the extra airflow. Both connect to standard flexible ducting.

🔗 Pairs With

• Waterproof Fan Kits

• Auto Fill Mini Float Valve

• Ultrasonic Mist Maker Kits

⚠ Shipping Notes:

• ✅ Free Shipping within the USA on all products.

• 🌍 International orders may incur customs fees, not included in the purchase price.