TOG is a rating system that stands for Thermal Overall Grade, a unit of measurement to calculate the insulation of a product at a thermal level. Commonly utilised in the textile and bedding industry, duvets and blankets will be given a TOG rating to reflect the degree of warmth. The higher the numbers, the warmer it will be. Don't be fooled into wanting to highest TOG however as it can become too hot. Instead, opt for one similar to this that is an ideal multi-season layer that will keep you cosy through spring and autumn but may perhaps need changing for summer and winter where you may want a lower - and - higher TOG.