Cool head. Higher ceiling.
Your body quits before you do. Above 39-40C core temperature, your nervous system throttles your muscles to protect you: pace drops, heart rate spikes, and your head still wants more. That is not weakness. That is a brake.
KELVIN is a stick-on cooling element you snap to activate on your neck, so you keep your grip while everyone else fades in the second half.
Proof, not hype
Neck cooling works mainly through perception. It lowers the heat signal to your brain and delays central fatigue, so you push harder at the same effort.
- +10.5% distance. Runners covered 3,030 m with neck cooling versus 2,741 m without, in a heat time-trial. Source: Practical neck cooling and time-trial running performance, Eur J Appl Physiol
- The brake is central. Above 39-40C your nervous system cuts muscle efficiency to prevent overheating.
- The neck is the spot. High thermoreceptor density near large blood vessels makes it the fastest signal to your brain.
- Honest note: KELVIN improves performance and your sense of grip through heat perception and central fatigue. It does not claim to lower your measured core body temperature, and it is not a medical device.
For endurance athletes
Fuel. Hydrate. Cool.
Gels and electrolytes keep your engine running. KELVIN adds what they can't: cooling on demand.
ENERGY GELS
Carbohydrates to keep your energy up on long efforts.
- ›Fuels your muscles with carbs
- ›No cooling effect
ELECTROLYTES
Salts and fluid to replace what you lose through sweat.
- ›Replaces sodium and fluid
- ›No cooling effect
KELVIN
An on-demand cold signal when the heat builds. Works alongside your gels and electrolytes.
- ›Snap to activate, exactly when you choose
- ›up to 4 hours cooling
- ›Nothing to swallow, no stomach load
How it works
Snap. Cool. Go.
One deliberate move, right when you choose. No towel, no melting ice. A switch.
Stick it on
Place the patch on the back or side of your neck, over the large blood vessels that carry the cold signal straight to your brain.
Snap to activate
Break the element so it turns fresh inside. Cooling starts on demand, exactly at the moment you decide.
Keep pushing
The cold signal lowers your head perception, so your brain gives the green light to keep working at the same effort.
FAQ
Before you race
The questions athletes ask us most before their first KELVIN race.
Does it stay on when I'm sweating heavily?
[Explain how the patch stays in place during heavy sweating: adhesive or tape used, and how it was tested (conditions, duration).]
How cold does it get, and how long does it last?
After you snap it, the element drops to [X]°C within [60] seconds and gives up to 4 hours of cooling. [Confirm both figures with test data.]
When should I snap it?
Wear it from the start and snap it when the heat starts to build, not before. As a guide:
- Marathon: around km 25.
- Hyrox: just before the sled push.
- Triathlon: at the start of the run.
Is it allowed in races?
[Only fill this in once confirmed, e.g. "We checked the current rules of Hyrox, World Athletics and IRONMAN on (date): ...". Link to the relevant rule where possible.]
Is it safe on my skin?
[Short answer on skin safety, e.g. dermatological testing.] See Safety & ingredients for ingredients, REACH testing and warnings.
Can I use it more than once?
[Single use or reusable? Explain briefly.]
How does it compare to ice or a wet towel?
Ice and wet towels depend on aid stations, warm up or melt within minutes and leave you wet. KELVIN is on your neck from the start and cools exactly when you snap it, with no aid station and no mess. See the comparison table further down this page.
Can I carry it in a gel belt or pocket?
[Yes/no, with size (X × Y mm) and weight (Z g), compared to a gel. Add a photo next to a gel below.]
How fast do you ship?
[Shipping countries, costs and delivery times.]
Can I return it?
[Return window and conditions.]
How do I dispose of a used patch?
[How to dispose of a used patch and the packaging.]
Cooling on demand
Snap it when it counts
Wear it from the start. Snap it when the heat starts to build.
Marathon
42.2 kmRight where the heat and the fatigue start to stack up.
Hyrox
8 × 1 km run + 8 stationsCool down going into the heaviest station of the race.
Triathlon
Swim · Bike · RunStage positions based on typical time per leg.
Compare
KELVIN vs the usual fixes
Ice, a wet towel or a cooling vest all cool you down. Only one fits in your race and works when you decide.
|
KELVIN
On demand | Ice | Wet towel | Cooling vest | |
|---|---|---|---|---|
| Weight | [X] g | Handed out at aid stations | Light, heavier when soaked | [Typical weight] |
| Timing | Snap exactly when you choose | Only at aid stations | Only where there's water | Before the start only (pre-cooling) |
| Mess | None | Melts and drips | Drips, soaks your kit | Bulky, needs a freezer |
| Price per race | €6.90–€9 (10-pack to single) | Free at aid stations | Low | [Typical price, one-off] |
Indicative comparison. KELVIN price per race based on current pack prices.
Safety & ingredients
Safe to wear. Clearly labelled.
KELVIN is made for use on the skin during sport. Below you'll find the product safety information we are required to provide under EU law.
Draft — to be completed and verified by a compliance specialist
Product safety (EU GPSR)
KELVIN is placed on the EU market in accordance with the General Product Safety Regulation (EU) 2023/988 (GPSR). The product is intended for single use on healthy, intact skin by adults during sport.
Product identification: [product name, type/model and batch number as printed on the packaging].
Ingredients & REACH
Ingredients: [list of ingredients of the cooling element and patch/tape].
The materials have been tested for compliance with Regulation (EC) No 1907/2006 (REACH) by [name of accredited test laboratory], test report [report number], dated [date]. The test was validated by the [manufacturer / importer].
Manufacturer & importer
Manufacturer: [company name], [postal address], [email / website].
Importer / EU responsible person: [company name], [postal address], [email / website].
Warnings
The following warnings are shown on this page and printed on the packaging:
- [Warning, e.g. for external use only.]
- [Warning, e.g. do not apply to broken or irritated skin; stop use if irritation occurs.]
- [Warning, e.g. do not open, puncture or swallow the cooling element.]
- [Warning, e.g. keep out of reach of children.]