FRIEDRICHSHAFEN ? German functional knitted fabric brand Fuse has developed what it claims is the lightest Santoni seamless knitted base layer garment for performance wear at just 70 grams per square metre. On display here at the OutDoor event in Germany, the new ?F-lighTex? short sleeved polypropylene/nylon base layer tee shirt clocked in at a mere 55 grams in total weight.