Rab/Ultrasphere 4.5 Sleep Mat

Minimalist's best solution



Rab is a brand founded in 1981 by British climber Robert Carrington, and produces highly reliable, high-quality items for extreme cold environments and alpine climbing around the world. In particular, the company has a reputation for its advanced technology and attention to detail when it comes to down and synthetic fiber insulation systems, which are the company's roots.

We have developed the company's first sleeping mat series, making it possible to have a one-stop experience when combined with sleeping bags. Ultrasphere 4.5 is a feather light air mat that combines the ultra-lightweight material TILT with an offset air chamber structure that prevents heat from escaping. Ultra-lightweight (370g), high performance (R value 4.3), and minimal pack size (18 x 9cm), it's the perfect solution for minimalists.

The newly developed tapered mummy shape pursues the balance between ultra-lightweight and high performance. By alternating the positions of the holes in the horizontally arranged air chambers, internal air convection is greatly reduced and excellent heat retention is achieved. Body pressure is accurately distributed, and the 8cm thickness makes it very comfortable to sleep on. The interior is equipped with a special two-layer TILT reflective film made from metal called TILT (Thermo Ionic Lining Technology), which reflects heat emitted from the body, greatly reducing radiant heat loss. This reduces the amount of structure needed to achieve consistent warmth, creating an amazing balance. The soft fabric also reduces the slippage of the sleeping bag. Equipped with a low-profile two-way valve, the included large pump sack quickly inflates the mat, and the stuff sack can be opened and closed from the side for easy access.

Mythic Ultra 120 Modular The ultimate lightweight sleep system is designed to be secured to an air mattress and insulated on the back, making it ideal for thru-hikes, multi-day mountain runs, and even minimalist car camping. Due to the tapered mummy shape, Wanderout / Insuration Sheet 00 Combined with this, it reduces condensation on the sleeping bag that protrudes from the mat, and also has an insulation effect. It is possible to live more lightly.


- R- VALUE 4.3
- 20D recycled polyester TPU coating
- Fluorocarbon-free DWR durable water repellent finish
- Equipped with a special 2-layer TILT reflective film derived from metal, which reflects heat emitted from the body, significantly reducing radiant heat loss.
- A unique structure in which the holes in the partition walls of the chamber inside the lightweight mat are shifted to significantly reduce air convection inside the mat and maintain warm air.
- Light weight with tapered mummy shape
- Low-profile 2-way valve allows for easy inflation and deflation
- Comes with pump sack
- Comes with repair kit
- Roll-away stuff sack included
- Light gray color
- Rab domestic genuine product


Pack size: approx. 18 x 9 x 9cm
Weight: 370g
R-VALUE : 4.3
Material: Fabric: 20 denier recycled polyester TPU coating
Attachments: stuff sack, pump sack, repair kit



Product code 09965-33-289