Instant cold packs are activated without refrigeration by squeezing them. Many reusable gel compresses and wraps can be frozen for cold therapy or microwaved for heat. Electric heating pads heat via an electric power source; some include a removable gel pack that can be warmed or chilled and inserted into a built-in sleeve.
Retention varies by product: some reusable cold packs advertise cold retention up to about 8 hours; insulated travel mugs commonly claim they keep beverages hot or cold up to about 6 hours; smaller gel masks and compresses typically retain treatment temperature only for short periods, commonly around 10–20 minutes.
Common materials include paper for disposable cups, plastic shells for cold packs, internal gel beads or pearls in many compresses, textile fabrics (for example, 100% polyester) for covers and wraps, and stainless steel for insulated mugs.
The electric heating pad described offers four settings—warm, low, medium, and high—with a noted temperature range from about 110°F to 140°F.
