Zerofit Thermal Bobble Hat - Black The Zerofit Thermal bobble hat is a cosy and stylish winter accessory designed to keep you warm in cold weather. The new thermal bobble hat has been developed in Japan with insights from the same innovation team that created the award-winning Zerofit Heatrub Ultimate base layer, and it’s now available in the UK, Europe and North America for the first time. The Thermal Bobble hat is the perfect winter wear to complete your cold weather wardrobe and combines with the ultimate base layer and leggings in temperatures as low as -10° Celsius. Care: Machine wash 40D (optimum temperature 30d). Do not iron, tumble dry or bleach. Drip dry in the shade. Product contains 7% wool so as with any wool product there will be a minimal amount of pilling (bobbling). This can be reduced by washing the product inside out and using an anti-pilling detergent.