The JK Audio Outerloop 3.5 provides you with a wireless link to your intercom system. This universal belt pack provides XLR connections for your existing 4-pin or 5-pin intercom headset, routing audio through a wired connection to your mobile device. Use your mobile device to call into your intercom phone bridge, station phone coupler, or any phone-based intercom app such as Clear-Com Agent-IC.Outerloop 3.5 includes a cable that plugs into the 3.5 mm TRRS headset/earbud jack of your mobile device, providing two-way communications. Separate Send and Receive level controls, a push-on, push-off Talk button, as well as a recessed sidetone level control let you adapt to any situation whether you are around the corner or around the world.Adapting to the mixed-up intercom world, model OUTERLOOP-3.5-F features both 4-pin and 5-pin Female XLR headset jacks, for male see JK-OUTERLOOP-35M which features both 4-pin and 5-pin Male XLR headset jacks. FeaturesHD Voice Compatible 7 kHz Wide-Band SpeechConnects to Phones and Notebooks with 4-conductor 3.5mm Headset Interface4-pin and 5-pin Male or Female Headset JacksSend and Receive Volume ControlsPush-On, Push-Off Talk ButtonRecessed Sidetone Level controlSpecificationsModel Outerloop: 3.5-FLoad Impedance: 50-600 ohmsPower: >50 mW into 150 ohmsFrequency Response: 50Hz - 15 kHzPower: >20 hours on one 9 VDC BatteryImpedance: 50-2000 ohmsSize: 3.5 in.