Outdoor Research has an excellent limited lifetime warranty, so if any parts of these pants fail (like the zippers) get in touch! As you can see, the Helium is significantly lighter than any other hooped bivvy bags. Helium Bivy weight vs non-hooped bivvies: Bivvy

Award-winning for its ultralight prowess, updated with our most durable lightweight Helium fabric with Diamond Fuse technology. This clamshell opening bivy is ideal for fast and light missions. The tapered shape of the Helium Bivy works best with tapered shape sleeping pads with narrower dimensions at the foot, ideally 19” or narrower. Rain pants typically fit casually to allow for layering. Our tester felt the women’s model was tight in the thighs. Assuming you want to keep your saddle-to-hood position consistent (the place you spend most of your time when riding a road bike), switching to this bar allowed me to lop off a not-insignificant 20mm off my stem length.They provide protection against unpredictable weather conditions and the elements of nature. Gaiters protect lower legs and ankles and stop stones and water from entering your boots, they’re crucial when navigating challenging terrain. Most rain pants are 2.5-layer, allowing decent breathability, good against skin feel, and solid waterproofing. More on rain layers in our Guide.

The Helium’s design is pretty standard: slightly tougher material on the floor (Hydroseal) and a thinner waterproof material on top (Pertex Shield+). It has a zipped opening at one end with separate retractable waterproof and mosiquito net hoods. There are hoops for three pegs at the head, two at the feet and none on the sides. The sleeve for the hoop is opened by velcro at one end and sealed at the other, meaning you save a bit of weight by not having metal eyelets. It has a very thin plastic pole which would worry you if it were in a tent but is fine for a bivvy. Compared to a regular bivvy, hooped bivvys have the advantage of providing additional – albeit extremely cramped – living room; more space for sleeping bags or quilts to loft; and the ability to close the bag around your head with either a mesh bug net or the breathable fabric without excess buildup of condensation. For very stormy weather or non-stop drizzle the Helium is not quite robust enough, but it’s perfect for summer mountain weather. A hooped bivvy is a sort of halfway house (halfway tent?), comprising a single layer of breathable fabric with the portion above your head held aloft by a pole.

Exterior Chest Pocket

I find the Helium Pants to be wonderfully breathable and had no issues at all with trapped moisture or overheating. I hiked in them and ran in them and was always very satisfied with how they regulated. Waterproofness – 5 Stars Fully taped seams and solid waterproof credentials are in place to stop a sudden shower ruining your night. Meanwhile, our testers found that the bag is also very breathable, even when the bivvy is completely sealed up. OK, you will still see some moisture build up on the inside, as is always going to be the case with a bivy bag – especially when used in the UK – but we’d say you’re not going to find many more breathable options than this. Features I like the fit a lot. The medium is true-to-size, as I wear mediums regularly. The cut is close but not slim, what Outdoor Research calls “Standard”. I could wear appropriate midlayers under the Helium II and still be comfortable in the high-20s (just below freezing). Style The bag doesn’t come with pegs and thus they’re not included in the weight. Unlike some other hooped bivvies, the Helium doesn’t stand up without pegs so really does need to be pegged out so you should factor those into your calculations (N.B. it’s quite common for manufacturers to exclude pegs in their total weights so this isn’t too scandalous).

The Helium Bivy is certainly a distinctive product due to the high, clam-shaped opening at its head, which utilises a single arcing pole to create a high (for a bivvy bag) ceiling. This makes for easy entry and exit and gives the user plenty of head space – after all, no one wants a claustrophobic bivvying experience. Pertex Shield + is a 2.5-layer membrane that focuses on breathability and comfort. Even in the snow. Durability I do want to note that Outdoor Research includes an Infinity Guarantee on all of its products, which is a lifetime warranty for parts. The company’s reputation for fixes is very high, and if a zipper did fail you could send it in. The hood on the Rab Kinetic Alpine 2.0 is of special note because it features an internal elastic band designed to ride directly on the forehead and turned out to be comfortable and effective, maintaining top-notch peripheral vision. You can actually find a bunch of garments that are made using the same technology, including the Helium Wind Hoodie, which we featured in our Outdoor 100 product guide last year.

The gloves feature an elastic seamless pad in the palm that is, according to Elastic Interface, 3D-moulded to prevent pressure points on nerves and improving blood flow. Constructed with a super stretchy material and offering superb mobility, this is the ideal rain shell for demanding activities The fit of the mitts is true to size and they feel excellent when riding, but my early testing indicates they aren’t the most breathable. However, this may be a price I’m willing to pay given just how pleasingly supportive they are (I am also generally a sweaty young Scotsman, so don’t take my initial impressions as gospel). Stay tuned. I’ve only managed to get out for one (cold) night in the Helium but I’m already a total convert to hooped bivvys.