NWT Jack Wolfskin Tech T size M (men’s) Weight: 102 g (size M) JERSEY PLAIN: light, soft, jersey knit fabric with stay-fresh properties and active moisture management On day hikes or trekking trips, when things get hot and sweaty, the lightweight TECH T-shirt will help you stay cool. It consists of a polyester jersey fabric that absorbs moisture and wicks it away from the skin so it can dry quickly. The fabric also minimises the build-up of unpleasant odours.