Rab Ascent 900

A very warm, down-filled sleeping bag for regular use in winter in the UK, though it will be found far too warm in summer! The Ascent 900 is suitable for temperatures around 0ºC to -8ºC. It is made with 650 US fill power duck down and Pertex® outer fabric.

The Ascent range of sleeping bags from Rab are duck down filled performance sleeping bags designed for regular use. The bags use durable and lightweight Pertex fabric. These bags offer fantastic value for money, quality build and construction, durability and low weight for warmth of the bags. The bags are designed in a semi rectangular shape that is more user friendly for general purpose use or for those buying their first down bag. They now use some recycled materials.

• 30D Recycled Pertex® Quantum (50gsm) with fluorocarbon-free DWR outer.
• 20D Recycled Nylon (38gsm) lining.
• 650 fill power R.D.S Certified European Goose Down with Nikwax fluorocarbon-free Hydrophobic Finish.
• Trapezoidal boxwall construction with differential cut, to maximise loft and warmth.
• Three-dimensional shaped neck collar to seal in warmth.
• YKK 3/4 length main zip with down filled baffle to trap warmth.
• YKK zipped internal stash pocket.
• YKK Anti-snag zip insert and anti snag internal zip guard.
• Wide mummy shape.
• Angled foot box for relaxed sleeping posture.
• Left and right hand bags can zip together.
• Zipped cotton sack with water-resistant base for home storage.
• Drawcord stuffsack included.

Outer: 100% recycled polyamide.
Lining: 100% recycled polyamide.
Fill: 650 USA fill power RDS Certified European Duck Down with Nikwax fluorocarbon-free Hydrophobic Finish.
Fill Weight: 900g.

ISO EN Sleeping Bag Temperature Ratings
ISO 23537 is the international standard for sleeping bags and requires a thermal manikin test which produces four temperature results - Upper Limit, Comfort, Limit (also written as Transition) and Extreme. There is no legal obligation to use this standard though most reputable brands do. There is an exemption for military sleeping bags and sleeping bags for extreme temperatures, ie a comfort range of below -25°C. 

Upper Limit: the highest temperature at which a standard man is able to have a comfortable night's sleep without excess sweating.
Comfort: the temperature at which a standard woman can expect to be comfortable in a relaxed position.
Limit (or Transition): the temperature at which a standard man can be not shivering in a curled position.
Extreme: the temperature at which a strong sensation of cold is to be expected and there is a risk of hypothermia.

For the purpose of these measurements, a "standard man" is assumed to be 25 years old, with a height of 1.73m (ie 5' 7", not very tall) and a weight of 73kg; a "standard woman" is assumed to be 25 years old, with a height of 1.60m (ie 5' 2.½") and a weight of 60kg.

It should be born in mind that the sleeping bag is just one part of the system and that other factors such as a good sleeping mat, how well fed you are and what clothes you are wearing, play a big part in how well you cope with cold temperatures. Plus, some people just feel the cold more than others - you'll know if you are one of them, and if so, plan accordingly.