Rab Neutrino 400 Review

Standing out from Rab's extensive collection of somnolent products is the feature-heavy, impressively packable Neutrino 400. Our testers have been through dozens of sleeping bags over the last 12 months, none of which have surpassed this piece of kit. That level of acclaim has earned it a Trail Gear of the Year 2023 award! Let's take a closer look.

The Neutrino 400 in Detail

Rab’s Neutrino range of hand-filled sleeping bags are fully featured and well designed, delivering a warm and comfy night’s sleep. Shopping from the Neutrino range is a joy too. There are 10 products, each filled with 800 fill power goose down – to start with. The across the range, fill weight increases in 100g increments from 200g to 900g. Hence, the naming system, with the number after each bag relating to its fill weight.

Eight bags are available in unisex versions. The 400 and 600 are available in women’s specific versions too, and the 300, 500, 700 and 900 have ‘pro’ versions with a more weather-resistant Pertex Quantum Pro shell.

All of this choice means you can fine-tune your selection precisely to your needs and the temperatures you’re likely to experience (how convenient). The alpine-inspired Neutrino 400 is a particular stand-out in the crowd. With a tapered mummy design, chevron-shaped baffles, angled footbox and -1°C comfort rating despite weighing just 775g, this is certainly one of the best sleeping bags for 2023.

Our Three Favourite Things

Improved eco credentials

Rab hand-fill their down sleeping bags on site in Derbyshire. Their precise, careful construction has earned the Neutrino range a long-standing and stellar reputation. The range continues to impress with the recent implementation of quite eco upgrades in 2022. Rab uses more recycled materials than ever, such as the 100% polyamide lining and recycled Pertex Quantum shell. Plus, they ensure that said materials recieve PFC-free DWR treatment. Rab describe the range as “lightweight in your packs and on the planet” with “exceptional packability and warmth-to-weight”

Clever baffles

Most sleeping bags use box-wall construction to trap the fill inside brick-shaped, horizontal pockets (baffles). Larger baffles give more space for insulation to loft, smaller baffles help stop the fill from spreading out. However, Rab designed special chevron-shaped baffles for this bag, primarily to reduce the amount of fabric needed compared to traditional horizontal baffles. The trapezoid box-wall baffle construction also allows the down to fully loft, eliminates cold spots and maximises warmth.

Excellent features

The Neutrino 400 is a fully-featured product with everything you could possibly expect or need from a sleeping bag. Additional zipper and neck baffles (on top of the main chevron baffles mentioned above) lock in warmth, and you also get an adjustable hood, ¾-length YKK zipper, angled footbox, internal stash pocket, cotton storage sack and waterproof compression sack. The fill is Nikwax’s hydrophobic down, the sturdy shell is made from a 20-denier Pertex Quantum nylon, and the lining is 20-denier recycled nylon.