SPARK isn't a medical device, and we don't claim to treat or prevent Raynaud's. It's a heated glove liner designed for the everyday situations Raynaud's sufferers actually find themselves in — delivering warmth to your fingertips at the moments they're most likely to go cold. SPARK can ease the discomfort when your hands run cold, but it isn't a substitute for medical advice or prescribed treatment. If you're under medical care, SPARK can be used alongside your existing routine.

Yes — and this is the starting point of SPARK's entire design. Most heated gloves on the market concentrate the heating elements on the back of the hand. That makes sense for skiers, whose palms generate metabolic heat from movement; but for Raynaud's, vasospasm starts at the fingertips and spreads inward. SPARK uses a three-zone heat density design: 100% at the fingertips, 50% across the palm, 30% on the back of the hand. All five fingertips (thumb to little finger) are wrapped with heating filaments across the back, sides and palm side — putting heat where vasospasm strikes first.

Yes. SPARK is 1.0–1.2 mm thick — about the same as a quality thin leather glove. In beta testing, wearers reported being able to type, use their phone, tap a card, hold a pen and grip a credit card without taking the gloves off. The thumb, index and middle fingers have stainless-steel conductive fabric woven in for touchscreen use — works directly on iPhone, Android and iPad. We deliberately designed the first generation as a liner you can keep on all day, rather than a medical aid you put on only when you need it.

8+ hours on the medium setting when paired with a 10,000 mAh / 5V 2A power bank, tested at room temperature (20°C). At 0°C, battery life drops by around 25–35% — to roughly 5–6 hours. We've chosen to be upfront about cold-weather performance rather than quote room-temperature figures as if they applied universally. The industry typically overstates battery life by about half, and we don't want to be the next brand that lets you down. If you need more runtime, you can carry a second power bank and swap on the go — SPARK's fully external power design was built for exactly that flexibility.

Yes — and our sizing commitment goes well beyond a standard 30-day no-questions return.

SPARK offers a 30-day no-questions return (UK law requires 14 days; we extend it to 30) for unworn items in their original packaging.

More importantly: if you've already put the gloves on and find the size isn't right, we'll send you a different size free of charge — within 14 days of purchase, up to 2 free size exchanges per order. We know glove sizing charts don't tell the whole story, and we don't want "what if they don't fit?" to be a barrier to giving SPARK a try.

You can also download our scale 1:1 sizing PDF from the Size Guide page — print it out and lay your hand on it to compare. It helps you get the size right first time, but if you don't, we've got you covered.