La Crosse Technology 306-605 Solar Window Thermometer with Solar Powered Backlight Delivers precise temperature readingsstraight from your backyard. Easily monitor temperature and track minimum/maximum records; the thermometer also features a solar cell that charges the backlight for nighttime illumination Solar Powered Backlight. Outdoor Temperature in F or C. Reads Easily From Inside. Records MIN & MAX Temperature with Auto Reset Clock with DST Indicator. Weather Resistant. Detachable for Window Cleaning. Automatic Backlight for Easy reading in the Dark Temperature Range: -13F to 158F. Power Requirements: Display: 1 "AAA" Alkaline Battery Included, Backlight: 1 "AAA" NI-MH Battery Included. Dimensions: 4.75" L x 1.07" W x 5.13" H