- Convenient sizing for many uses, either by itself or to rotate as a refill in our warm systems for continuous uninterrupted cold therapy. Stays flexible when fully frozen, to mold around painful area. Quickly reaches freezing temperature. Maintains low temperature longer for optimum therapeutic benefit. Non-toxic fill enclosed in latex-free vinyl. Durable enough to be used several times a day. Ergonomic designs for specific areas, such as the neck, shoulder, back or wrist. Size options (each sold separately); 4.