This is a single additional beltpack for the Hollyland Mars T1000 wireless intercom system (part MARST1000-BP). The Mars T1000 lets a small crew - camera operators, a director, floor managers, lighting or event staff - talk to each other hands-free in full duplex, without cables, from up to 1,000 ft (300 m) line of sight from the base station. Each base station supports up to four beltpacks, so this unit is used to replace a lost or damaged pack or to bring a system up to its full crew. The beltpack runs on the 1.9 GHz band with GFSK modulation, has an OLED display with Mute and Talk controls, a 3.5 mm headset jack, a 3.5 mm tally output for an external tally lamp, and a USB-C port for charging and firmware updates. Its built-in 1,600 mAh lithium-polymer battery gives more than eight hours of use per charge, and the base station's USB-A ports can charge beltpacks directly. It measures 100 x 58 x 22 mm and weighs 180 g. A headset is not part of this beltpack SKU; it must be paired to a Mars T1000 base station.