Thats not true because it is not odorless. And i dont know why they put this on the package like that.
But it is a natural odor from chrysanthemum flowers.


"How It Works
ThermaCELL uses revolutionary, patented technology to dispense a small amount of repellent into the air over a long period of time. ThermaCELL is powered by a butane cartridge which provides the cordless, portable heat necessary to operate the device (batteries are not needed). It directs the heat to a metal grill. A mat saturated with Allethrin, a copy of a naturally occurring insecticide found in chrysanthemum flowers, is placed on top of the metal grill. The heat generated by the butane cartridge vaporizes the repellent allowing it to rise into the air, creating a 15 x 15 ft (225 sq ft) “Mosquito-Free-Zone” in minutes. The repellent is very unpleasant to mosquitoes, but when used as directed, will not harm humans or pets."