What is a hydrocollator?

Hydrocollator - A hot, moist pack used to treat bruises, sprains, and muscle spasms. A pack is heated to about 65°C and applied to the injured region. Dry towels are placed between the pack and the skin to prevent burning. The heat reduces pain by increasing blood circulation at the body surface.

Above retrieved from Answers.com

Viper1

Hydrocollator - A hot, moist pack used to treat bruises, sprains, and muscle spasms. A pack is heated to about 65