Ambient Weather TX-8300 Wireless Thermometer for WS-8365 and WS-8400 Projection Clock Additional or replacement wireless thermometer for the ws-8365 and ws-8400 series projection clock 2 x AA batteries required (not Included) Range: -4 to 140 DegreeF alkaline batteries, -22 to 140 DegreeF lithium batteries Accuracy: 2 DegreeF Resolution: 0.1