Thermoreg Long Sleeve Baselayer Our iconic base layer has had a re-design. Now incorporating our body temperature regulating tech, ThermoReg, this base layer can help you train harder. Coming in a variety of colours, you will look great whilst being prepared for the elements 92% Polyester 8% Spandex ThermoReg Technology creates an insulating layer that retains warmth while avoiding heat build-up in key areas. Allowing your body to regulate it's temperature.