Rab Neutrino 400 Review

The Rab Neutrino 400 is a great all-around sleeping bag with recycled materials, an effective draft collar, and good ventilation, but its 800FP down insulation can't quite keep up with the 850FP and 900FP down found on other high-end bags.

Performance Comparison

Warmth

The 400 in the name Rab Neutrino 400 signifies the 400 grams of down insulation it contains. In English units that translates to 14.1 ounces and that quantity is actually a little less than average for a bag with this warmth. That might be because the down is lofty 800 fill power. This insulation, combined with a cozy neck baffle to seal in heat, earns the Neutrino a 20F temperature rating. In our tests, the rating seemed to be accurate.

Weight

The Neutrino 400 features a streamlined mummy design with a strong taper from the head to the foot of the bag to minimize materials and overall weight. On our scale, a size long weighed in at 1.91 lbs. That's nearly the same weight as our favorite 20F bags from Western Mountaineering and Feathered Friends. However, we believe those bags provide more warmth than their 20F temperature ratings while the Neutrino merely meets it. Therefore, we think the Neutrino has a great, but not best-in-class, warmth-to-weight ratio.

Comfort

All of our testers were fans of the supple 20-denier recycled nylon used to line this bag. They also appreciated that the outer shell incorporates recycled Pertex Quantum. We were less pleased, however, with the taper at the foot of the bag. This taper is stronger than that seen on many other sleeping bags and several testers complained that the foot box felt uncomfortably constrictive. In contrast, the upper body dimensions seemed rather spacious for a lightweight model.

Packed Size

We were able to squeeze the Rab Neutrino 400 down to an impressively svelte 8.9 liters of volume. That's near the top of the field for bags that offer the same amount of warmth. Keep in mind that we achieved those results with a third-party compression sack. The Neutrino comes with its own sack but it's a roll-top waterproof design. The waterproofness may be desirable to some but the roll-top closure makes it fairly hard to pack it down fully.

Versatility

This bag's lightweight design and 20F temperature rating limit its versatility to some extent. The lightweight design sacrifices the bag's spaciousness and we worry it's probably too constrictive for extended trips. At the same time, the 20F temperature rating and minimal venting possibilities make this bag too warm for many summer backpacking applications. Instead, it's a bag that's best suited for ounce counters or mountaineers looking to shave a little weight for colder trips during the shoulder seasons or at high elevation.

Features & Design

Our favorite feature on the Rab Neutrino 400 is the neck baffle. This baffle wraps 360 degrees around the collar of the bag to snuggle your neck and shoulders and prevent heat from escaping out of the main body of the bag. There is also a small stash pocket adjacent to the baffle to stow a headlamp. Unfortunately, the stash pocket isn't large enough to store most larger smartphones.

Value

The critical question for a premium sleeping bag like the Rab Neutrino 400 should not be: is the bag good? This bag is unquestionably good. The critical question instead should be: how does the bag compare to other premium sleeping bags? In this regard, it also does pretty well--it performs better than most similarly priced bags. But compared to the absolute best premium bags from Western Mountaineering and Feathered Friends, the Neutrino is a clear step behind. For this reason, we don't consider it an exceptional value for the price.

Conclusion