KeySonic ACK-340 RF+. Device interface: RF Wireless, Keyboard layout: QWERTZ. Frequency band: 2.4 GHz, Wireless range: 10 m. Keyboard dimensions (WxDxH): 218 x 150 x 21 mm, Keyboard weight: 0.28 kg. Battery type: AAA. Operating temperature range (T-T): -5 - 50 °C, Storage temperature range (T-T): -20 - 65 °C, Operating relative humidity range: 10 - 85 %