Controlled therapy with TWO SURFACES. The dark blue plush side offers a slower release therapy for subacute injuries while the light blue rapid release side delivers immediate cold therapy for acute injuries. Chill them in the freezer or warm them in the microwave. Gelway’s reusable Duo-Soft Packs retain cold and heat longer than traditional hot/cold packs and can be placed directly on skin. A variety of shapes and sizes available. Personalize each to promote your practice.