Fiamma Ultra Box 500 Storage Box
External storage is a constant negotiation in any motorhome build, and the Ultra Box 500 is Fiamma's larger rear-mounted answer to it — a genuinely sizeable exterior box built to take the bulky, awkward gear that never fits neatly inside.
Key features
- 500-litre storage volume
- Open dimensions of approximately 147×83×103cm
- Closed (travel) dimensions of approximately 147×58×70cm
- Weighs around 17kg empty
- Designed for rear-mounted external fitting on motorhomes
RV use case
This is aimed squarely at motorhome owners who've run out of patience trying to fit chairs, a table, hoses, levelling gear and outdoor mats into internal storage. The rear-mounted external position keeps bulky items out of the cabin entirely, which matters for weight distribution and simply for reclaiming internal living space. Payload needs to be factored in carefully — 500 litres of gear adds up in weight, and it's worth weighing loaded to confirm you're still within your motorhome's rated limits.
Pros
- Genuinely large capacity for bulky outdoor gear
- Keeps awkward items out of the cabin, freeing up internal space
- Compact closed dimensions relative to the open storage volume
Cons
- Adds real weight to the rear of the vehicle — payload planning is essential
- External mounting means the box and its contents are exposed to weather and road grime
- Rear overhang and departure angle need checking before fitting on some chassis
Best for
Motorhome owners needing genuine external capacity for bulky outdoor gear — chairs, tables, levelling blocks and hoses that otherwise clutter internal storage.
Verdict
Five hundred litres is a serious amount of external storage, and for motorhome owners drowning in outdoor gear, that's exactly the point — just weigh it properly once loaded, and check departure angle before committing to the fit.
Fiamma Ultra Box 500 Storage Box
Another angled view of the box mounted on the carrier
Interior view showing the mesh compartments and straps
Dimensions diagram for the Ultra Box 500