Get fast, soothing relief that goes deep into your sore muscles by creating a moist heat when microwaved. It requires no boiling or electrical wires, just 1 to 1-1/2 minutes in the microwave. The TheraBeads are designed to conform to any part of the body, giving a gentle, snug fit. Recommended by doctors, hospitals, clinics, and physical therapists. Microwave instructions included.