What One Air Box 4 Refill Cartridge Covers
The Air Box 4 is the 2000 CFM housing with 10 in flanges, and it carries four carbon cartridges rather than one. This listing is a single cartridge, so a full refill is four of them. Media is 100% activated charcoal made from premium virgin coconut shell, which is the same grade used across the Stealth range. The housing itself is steel and lasts indefinitely, so the running cost of a box filter is entirely the cartridges. That is the trade against a cylindrical filter, where a spent unit is scrap. On a room pushing close to the rated airflow, cartridges load faster than the published window suggests.
Reading When an Airbox Carbon Filter Is Spent
An airbox carbon filter gives two warnings before it fails outright, and both are easy to miss. The first is odour breaking through at the exhaust when the room is at its warmest, usually late in lights-on. The second is a drop in airflow as the loaded carbon adds static pressure, which shows up as a fan working harder for less. Neither arrives on a schedule, because humidity and temperature drive carbon loading more than hours do. Replace all four cartridges together rather than rotating them. Air takes the easiest path, and a fresh cartridge next to three spent ones does very little. Keep the spent frames for reference on size before fitting the new set. Carbon loading tracks the volume of air that has passed through it. A busy room burns media faster than a quiet one on the same calendar.
Key Features
- Fits the Air Box 4 housing: The 2000 CFM unit with 10 in flanges, which carries four cartridges.
- Sold as a single cartridge: A complete refill for that housing means four of these.
- Premium virgin coconut charcoal: 100% activated carbon media, the same grade across the Stealth range.
- Housing outlives the media: The steel body stays, so running cost is cartridges rather than whole filters.
- Change as a full set: Mixing fresh and spent cartridges lets air bypass the working carbon.
Technical Specifications
| Specification | Value |
|---|---|
| Brand | Air Box |
| Product | Refill Carbon Cartridge |
| Part Number | HT4503 |
| Fits | Air Box 4 |
| Quantity | Single cartridge |
| Cartridges Per Housing | 4 |
| Housing Rating | 2000 CFM, 10 in flanges |
| Media | 100% activated charcoal, premium virgin coconut |
| Typical Service Life | 18 to 24 months |
| Max Operating Temperature | 176 F |
| Returns | 14 days from delivery if unused, with a 30% restocking fee and return shipping paid by the customer, per the Air Box manufacturer policy |