Oregon Scientific John Deere Waterproof Floating Thermometer Floating thermometer for hot tubs, pools, lakes; wireless transmission to weather stations (sold separately) Three channel selectable for use with weather stations receiving other remote signals Waterproof casing is chemical and UV resistant Works with WMR968, WRB308, BAR122HGLA, and BAR898HGA stations Dimensions: 4 by 4 by 7 inches; requires two AAA batteries (included)