A New Balance in Sleeping Comfort


Rab was founded in 1981 by British climber Robert Carrington. Since then, the brand has continued to produce highly reliable equipment, developed in some of the world’s harshest cold environments and alpine climbing conditions.

The Ultrasphere 5 Wide is a featherlight air mat that combines ultra-lightweight TILT material with an offset baffle construction designed to minimize heat loss. Weighing 440g with an R-value of 5.5 and packing down to a compact size (19 × 9 cm), it offers a well-balanced option for those seeking dependable warmth within a minimal setup.

At Wanderout, we selected the Wide version to reduce cold air from the sides while allowing more room for stable, comfortable sleep. Compared to the regular 51cm width, the Wide measures 64cm across, helping prevent your sleeping bag from slipping off the mat and ensuring greater stability. Its insulation performance is suitable not only for spring and autumn but also extends into colder seasons.

The newly developed tapered mummy shape pursues a balance between ultra-light weight and high performance. By offsetting the perforations between horizontally aligned chambers, internal air convection is reduced, enhancing thermal efficiency. The 8cm thickness distributes body pressure effectively and provides a stable sleeping surface.

Inside, Rab’s TILT (Thermo Ionic Lining Technology) incorporates two layers of metallic-based reflective film that reflect radiant body heat, significantly reducing heat loss. This allows the mat to achieve high thermal performance without adding unnecessary structural weight. The soft-touch fabric helps prevent your sleeping bag from slipping. A low-profile two-way valve enables easy inflation and deflation, while the included pump sack allows for quick setup. The side-opening stuff sack ensures smooth packing and unpacking.

Due to its tapered shape, the foot area is slightly narrower. When paired with the Insulation Sheet 00, condensation on portions of the sleeping bag extending beyond the mat can be reduced, while adding supplemental insulation.


- Achieves R-VALUE 5.5 at just 345g
- Dual-layer TILT reflective film reduces radiant heat loss without increasing weight
- Offset lightweight cut-out construction traps warm air inside
- Tapered mummy shape for reduced weight
- Low-profile two-way valve for easy inflation and deflation
- Includes pump sack
- Includes repair kit
- Roll-away stuff sack included
- Dark Pewter color
- Official Rab Japan product


Size: 183 x 64 x 8cm
Pack size: 19 x 9cm
Weight: 440g
R-VALUE : 5.5
Material: Fabric: 20 denier recycled polyester 85% nylon, 15%
Includes: stuff sack, pump sack, repair kit



Product code 09965-53-003