What is "therm-a-rest"

Therm-a-Rest is an American outdoor product company specializing in camping mattresses, sleeping bags, camp chairs, hammocks, cots and pillows. Therm-a-Rest began as a line of self-inflating camping mattresses, invented in the early 1970s by two former Boeing engineers and avid backpackers. The company was initially named Cascade Designs, which is now the parent company of Therm-a-Rest and other outdoor brands.