Warmth for effective pain relief and enhanced muscle recovery in clinical and rehabilitation settings. The Gelway Hydrocollator Moist Heating Hot Pack is easy to use providing up to 30 minutes of soothing therapy for sore muscles and joints. With six sizes to choose from, the Hot Packs are designed to fit virtually every body contour. Washable and reusable. These convenient Hot Packs can be heated using Hydrocollator Heating Units, or for home use, in hot water or the microwave.