TIMEX 4 ½ Suction Cup Window Hygrometer. Made of clear see thru flexible plastic. Easily attaches to any window surface. Hygrometer measures relative humidity (RH). Humidity accuracy is +/- 5% from 20% Relative Humidity to 80% Relatively Humidity. Bright red hygrometer pointer. Plastic housing protects the actual hygrometer from all the weather elements. Backed by Timex two year limited warranty. Size of the product 4 1/2 diameter.