The Hydrocollator® Moist Heat Hot Pac provides nearly immediate, soothing relief and is designed to fit around your neck to deliver the most effective moist heat therapy. Simply immerse the hot pack in your Hydrocollator® heating unit, and once it's steaming hot, place it in its comfortable terry-cloth cover and apply to your aching neck for up to 30 minutes of deep, penetrating relief. You get hundreds of applications from a single Moist Heat Hot Pac. This moist heat treatment is all-natural too. It's especially effective for the treatment of pain associated with arthritis, myelofibrosis, back problems, and muscle strains and spasms.