Sea to summit reactor thermolite compact plus sleeping bag liner increases sleeping bag performance by up to 20 f 11 c with dual weight thermolite fabric our regular 80 gm is combined with panels of 110gm thermolite in the core body and foot bed areas adding extra warmth where most needed the compact shorter design shaves off excess weight while giving maximum warmth for torso and feet first dual fabric sleeping bag liner 110gm2 thermolite panels in torso and foot areas adds