La Crosse Technology WS-8418U-IT Atomic Digital Wall Clock with Moon Phase Atomic indoor wall clock with moon phase and indoor/outdoor temperature display from La Crosse; sets automatically to WWVB signal Large digital display; alarm clock function with snooze button Outside TX37U-IT sensor transmits data every 4 seconds at 915MHz from up to 330 feet away; manual setting option Requires separate purchase of 4 AA batteries; low battery indication icons for both clock and sensor Clock measures 10-1/4 inches wide by 1-1/6 inches deep by 9-3/4 inches high; 1-year limited warranty.Dimensions:Sensor: 1.50 L x 0.83 W x 5.05 H inches