Sea to Summit

£370

1095g

3 zips, roomy shape, 2 lengths

high cost

Fill: 550g 750+fp RDS Ultra-Dry down Shell: 20D nylon

Construction: box wall

Zip: YKK, 2-way full-length left side, foot zip, half-length zip right side

Length: regular, long

Rating: comfort -4C, lower comfort -10C seatosummit.co.uk

The Ascent II is an unusual bag. It’s not a mummy shape but a tapered rectangle with a hood, a baffle and a shaped foot. The shape means it’s much wider than mummy bags, allowing complete freedom for stretching out and moving in your sleep. For anyone who finds narrow bags confining it could be ideal. The Ascent II also has three zips to give multiple ventilation options. There’s a standard full-length side zip on one side, a half zip on the other side, and a foot zip. All the zips are two-way ones. With them you can fold back the top of the bag as a mini quilt or open the bag flat for use as a full quilt as well as unzip sections for ventilation.

There are thick baffles – Sea to Summit calls them over-sized – behind the zips, and round the hood and neck. The internal baffles on the chest are vertical not horizontal, to prevent down going to the sides. 60% of the down is on the top, 40% on the bottom. In standard mummy bags I don’t like this feature as I often turn over with the bag, so the base ends up on top. However, it’s fine on the Ascent as I can easily turn over inside it.

The Ascent is an innovative product that I really like. The comfort is superb. The weight is reasonable given the warmth and the size. I would expect it to keep me warm at the lower rated temperatures despite the width. The cost is high, but this is a top-quality bag.