OMM Kamleika Overmitt Review

Overview

The OMM Kamleika Overmitt is a 30g-per-pair waterproof hand shell built from the same stretch-knit Nylon/PU fabric as OMM’s well-regarded Kamleika jacket range. It’s a waterproof overmitt designed for foul-weather protection, and can be worn directly against the skin or pulled over a glove or insulating mitt. The target audience is mountain runners, fell racers, and anyone building a modular hand-layering system who doesn’t want a 50g+ Gore-Tex lobster claw eating up their kit allowance.

Key Specs

Spec	Detail
Weight	30g (per pair)
Waterproof Rating	20,000mm hydrostatic head
Breathability	20,000 gsm/24hr
Fabric	Kamleika — stretch-knitted Nylon with PU membrane
Technology	37.5 Technology (vapour management micro-particles)
Sizes	S / M / L
Features	Extended cuffs, low bulk construction, reflective logo, stretch fit
Comparison	See how Kamleika Overmitt compares to similar gear

Performance

Waterproofing and weather protection

The numbers here are not shy. A 20,000mm hydrostatic head and 20,000gsm/24hr breathability sit alongside the durability of a Nylon face fabric. For context, those figures match or beat most dedicated hardshell gloves costing two or three times as much. Reviewers of the broader Kamleika line have noted that performance seems to excel even past these impressive metrics in real-world conditions. For such a light and seemingly thin material, it does an awesome job of keeping out the rain. That tracks — the PU-backed Kamleika fabric is a genuine membrane construction, not a DWR-only treatment that’s going to wet out after an hour in a Welsh downpour.

Stretch, fit, and comfort

This is where the Kamleika family earns its reputation. Made with Kamleika fabric, it offers 4-way stretch for natural movement, breathable waterproof protection, and a soft feel that resists rustling. The rustle-free quality matters more than it sounds — to those who spend whole days running in the mountains, it can make a tough experience just that little bit more bearable. The stretch fit also means the mitts pull on and off quickly, which matters in the field. When your hands are cold and you’re fighting a sudden squall, a fiddly mitt is genuinely dangerous. Using an overmitt allows you to easily switch between the warmth and protection of a mitt and the dexterity or heat-shedding of a thinner glove underneath — and the Kamleika’s stretch makes that transition as frictionless as a waterproof shell layer can be.

Breathability and moisture management

The 37.5 Technology embedded in the fabric is worth a mention, though I’d be careful not to oversell it. 37.5 Technology has been added to the Kamleika fabric to improve vapour management and maintain a comfortable active temperature. OMM’s own testing found that runners wearing Kamleika with 37.5 Technology were able to maintain a stable temperature and regulate internal moisture when switching between flat running and ascents. In practice, this is a nice bonus rather than a magic solution — any waterproof shell will accumulate interior moisture when you’re working hard. Think of the 37.5 particles as helping at the margins, not replacing the need to regulate output or use a wicking glove liner underneath.

Layering system

OMM’s intended use case is pairing these over the Core Mitt for maximum warmth, or pairing the Kamleika Overmitt with a pair of gloves for the best of both worlds. They are perfect to use as an outer layer to weatherproof more basic gloves, or to stash in a pocket for emergencies. The extended cuffs are a thoughtful detail — they create overlap with jacket sleeves and prevent the classic gap where a rogue gust drives rain up your wrist.

Packability

At 30g for the pair, these compress to almost nothing — smaller than a golf ball when stuffed into a race vest pocket. They pack down small and weigh next to nothing, making them perfect for fastpacking, fell running, or ultralight adventures where every gram counts. That’s the core value proposition: always-available storm insurance at a cost of roughly one gel’s worth of weight.

Durability — a word of caution

This is where I want to be honest with you. The Kamleika fabric is inherently a compromise between stretch/comfort and robustness. The fabric is so soft and stretchy that it is inevitably going to be less durable than heftier alternatives — but it’s so much nicer to wear when running compared to a lot of superlight shells that you can forgive this trade-off. Forum discussions about Kamleika jackets more broadly do surface some seam and stitching concerns, with the problem being the combo of very stretchy fabric and not-very-stretchy stitching causing the stitching holes to widen quickly. I haven’t found specific seam-failure reports for the overmitts themselves, but the same structural tension applies at this scale. Treat these as a performance running accessory rather than a bomber mountaineering glove, and they’ll serve you well. If you’re grabbing branches, scrambling on sharp rock, or using them daily in abrasive conditions, longevity will be shorter than the specs imply. Also note: like virtually all PFC-free treatments, the DWR will require more regular re-proofing than older fluorocarbon finishes, particularly after sustained use in mud and muck — neglect it and performance will drop off faster than you’d expect.

Pros & Cons

Pros

• Exceptional weight-to-waterproofing ratio — 30g for a genuine 20,000mm membrane shell
• 4-way stretch means the mitts move with you, not against you
• Soft, quiet fabric — no distracting rustling on long days out
• Extended cuffs seal against jacket sleeves effectively
• Low enough bulk to live permanently in a race vest pocket
• Pairs cleanly with thin gloves or insulating mitts for a full layering system
• 37.5 Technology adds a marginal but welcome assist with moisture management

Cons

• Zero insulation — these are a shell only; you need a liner glove in genuinely cold conditions
• Long-term seam durability is a legitimate concern with the stretchy Kamleika fabric
• DWR requires regular maintenance to sustain performance
• No closure mechanism (no wrist strap or cinch) — fit relies entirely on the stretch
• No touchscreen compatibility — you’re pulling these off to use a phone

Who Should Buy This

The Kamleika Overmitt is purpose-built for ultra marathon race rules and high-output mountain pursuits where you need genuine waterproof protection without committing to a dedicated insulated glove. The ideal buyer is a fell runner or fastpacker who already carries a thin liner glove and wants a sub-30g shell to drop over the top when the weather turns. It’s also a sharp pick as mandatory kit for events like the OMM itself, where the weight penalty of a heavier mitt system isn’t justified. If you run cold and need warmth as much as waterproofing, pair these with OMM’s own Core Mitt — the combination covers both bases. If you’re primarily a hiker expecting heavy daily use in rough terrain, something built from a beefier face fabric will serve you better long-term.

Verdict

The Kamleika Overmitt does exactly what it promises: delivers credible waterproof protection and a genuinely comfortable, stretch fit in a package that weighs less than a typical energy bar. The 37.5 Technology and 20,000mm rating make it a technically serious product, not a token rain cover. The main honest caveats are the zero insulation, the DWR maintenance requirement, and the known long-term seam vulnerability that comes with any ultra-stretch waterproof shell. If you go in knowing you’re buying a refined shell layer rather than an all-conditions glove, this earns its place in a fast-and-light kit list. 7.5/10.