Deflecto Reusable Cool and Heat Pack for Lower Back eases pain, muscle tightness and menstrual discomfort - with an easy transition between hot and cold cycles. An easy fastening belt design provides secure cooling and pain relief to target the lower back area, applying the pack cold helps to reduce swelling, inflammation, fevers and sprains. Designed for hot and cold use, the pack stays flexible when chilled and soft when heated. To use, let the pad cool completely after heating. Placing a hot pad directly into the freezer can damage the material and reduce product life. To prevent moisture buildup or freezer burn, place in a ziplock or freezer-safe bag. Freeze or refrigerate for at least two hours, or overnight for best results.