The LKR-11 ListenTALK Receiver Pro is a one-way device designed for those participants that only need to listen to ListenTALK group conversations. The LKR -11 is equipped with Listen Technologies ergonomic design, near field communications, encryption technology for added security, easy to use volume control and quick visible status via the OLED display. ListenTALK Receiver Pro is the simplest option for one-way communication among groups of two or more people in any environment. In addition to the included Listen Ear Speaker, ListenTALK can be used with standard smartphone earbuds or Listen Technologies headphones.Main Features: Fast and simple one-way communication Simple up and down volume control Encryption technology for added security Compatible with standard earbuds and Listen Technologies headphones Long-lasting lithium-ion rechargeable batteries Optional Alkaline Battery CompartmentWhat’s Included: One (1) LKR-11 ListenTALK Receiver Pro One (1) LA-365 Rechargeable Li-ion Battery One (1) LA-401 Universal Ear Speaker One (1) LA-445-BK Breakaway LanyardSpecifications:Physical: Dimensions: (H x W x D) with Belt Clip 10 x 5.4 x 2.4 cm (3.93 x 2.13 W x 0.93 in.) Unit Dimensions (H x W x D): 10 x 5.4 x 1.6 cm (3.93 x 2.13 W x 0.63 in.) Unit Weight: 79 g (2.79 oz.) Shipping Weight: 206 g (7.20 oz) with 454 g (1.0 lbs.) minimum Enclosure material: PC ABS Plastic Color: Black, Chrome ButtonsIndicators: Display- 64 x 128 OLED, Variable brightness LED- RED/White multifunction (Mute, Charge Status) User Controls: Volume up, Volume Down, Power/Status Programming: Via software and USB port on unit or via software and USB port on Docking StationConnections: Headset- 3.5mm TRRS, CTIA complaint USB- Micro USB, Control and Charging Charger- 4 Contact, Control and ChargingAudio: Headphone Output: Speaker Load- 16 – 32 ohm load Max Output Power- 67 mW, 16 ohm load, Threshold of ClippingSystem: Frequency Response- 40 Hz to 15 kHz +/- 3dB, 22kHz low pass filter SNR- 70 dB, A- weighted, Threshold of Clipping THD- 0.5% @ 1kHz, 22kHz low pass enabledRadio:Operating Frequency: 1920 to 1930 MHz – North America 1880 to 1900 MHz – Europe, AustraliaTypical Range: Indoor 100 m, Outdoor 200 m, depending upon conditions – North America Indoor 150 m, Outdoor 300 m, depending upon conditions – Europe, AustraliaModulation: GFSK – FHSS TDD/TDMA/DCASecurity: Subscription- 40 bit (Pin Free) Authentication- 32 bit Encryption- 64 bit NFC Frequency (Near Field Communications): 13.56 MHzPower and Battery Management:Battery Type: Lithium ion, rechargeable non-proprietary removable, 1200 mAh Optional- 3 AAA Battery CompartmentTypical Operating Time: Li-ion – 12 Hours AAA 7 Hours Typical Charge time: 4 HoursPower Save Modes: Power down on loss of signal Power down on disconnection of headphone (1 min) Power down on chargingEnvironmental:Temperature: Operation- -10 C (14 F) to 40 C (+104 F) Storage- -20 C (-4 F) to 50 C (+122 F) Relative Humidity 0 to 95% relative humidity, non-condensingCompliance: Standards: FCC part 15, ICS-03, CE, RCM, RoHS, WEEE