ZeroFit Ultimate Heatrub Baselayer White

The ZeroFit Ultimate Heatrub Baselayer Shirt is the warmest baselayer in the ZeroFit range, and it’s earned that reputation the hard way, through proper testing, not marketing fluff.

Independently tested and proven to be five times warmer than a standard baselayer and twice as warm as a sweater, the Ultimate Heatrub delivers serious cold-weather performance while remaining impressively thin and comfortable. It’s designed for people who spend long days outdoors and don’t want bulky layers restricting movement.

At the heart of the Ultimate is ZeroFit’s innovative Heat Thread technology. These specially engineered fibres are activated by even the smallest movements, gently brushing against the skin to generate warmth instantly. Once created, the clever fabric construction traps and retains that heat, keeping your body temperature stable in harsh conditions.

Unlike many thermal baselayers, the Ultimate does not rely on compression to keep you warm. This means greater comfort, unrestricted movement, and a more natural fit, making it ideal for motorcycling and other active outdoor pursuits where flexibility matters.

The slightly looser neckline is a deliberate design choice. During development, tighter necklines were found to cause overheating, so the Ultimate allows excess heat to escape when needed, keeping you warm without becoming uncomfortable.

Extensive testing at Japan’s prestigious Boken Institute resulted in an impressive Heat Retention Rating of 0.78. To put that into perspective, a standard baselayer typically measures 0.1 to 0.14, while a sweater averages around 0.3.

Built to perform in temperatures as low as -10°C, the Ultimate Heatrub Baselayer Shirt is ideal for motorcycling, hiking, fishing, skiing, sailing, workwear and everyday cold-weather use. Thanks to its exceptional warmth, there’s no need to pile on multiple layers, making it a cost-effective and practical solution for staying warm.

Product Benefits

• Independently tested and proven to be five times warmer than a standard baselayer
• Generates instant warmth through movement-activated Heat Threads
• No compression fit, warm without feeling tight or restrictive
• Replaces multiple bulky layers with a single lightweight garment
• Excellent stretch for comfort and freedom of movement

Sizing Note

The Ultimate Heatrub Baselayer Shirt is constructed using an advanced four-way stretch fabric, designed to adapt to a wide range of activities and body movement.

It fits slightly more snug than the ZeroFit Move baselayer. We recommend ordering one size up from your usual t-shirt or polo shirt size for optimal comfort.

*Sizing guidance assumes a standard chest and abdomen fit.

Garment Construction

Acrylic 68%
Nylon 21%
Wool 7%
Polyester 2%
Polyurethane 2%

Optimal Temperature Range

-10°C to 10°C

Suitable For

Motorcycling, scuba, golf, hiking, equine sports, sailing, fishing, skiing, gardening and workwear.