No need for multiple additional layers due to the warmth generated by the innovative Heat Threads on the inside of the garment Technologically enhanced 'Heat Threads inside the garment are activated through even the slightest of movements, gently brushing against the skin to generate positive warmth instantly and the construction of the Zerofit Heatrub Ultimate means the heat is retained. Unlike other baselayers, the Ultimate does not work on the basis of 'compression for heat' - so not only does it provide greater warmth, but you also won’t feel restrained by an inability to move freely, making it one of our most comfortable baselayers. It also features a slightly looser neckline design, which allows some heat to travel out away from the body - during testing and development of the Ultima.
