The Rugged Radios PLUS2-HK rear-seat expansion kit turns a 2-place Rugged Offroad Mono intercom system into a 4-place system, adding two helmet kits and two 16-foot intercom cables for the back seats. Rear passengers plug straight into the open rear ports of your existing Rugged intercom — no new intercom needed.CompatibilityThis is the Offroad Mono version, matched to Rugged Offroad Mono intercoms such as the 696 PLUS. It is not wired for the STX Stereo intercom — stereo systems use the PLUS2-STX version of this kit. Within the Mono line, PLUS2-H48 supplies AlphaBass behind-the-head headsets and PLUS2-OTU supplies Ultimate over-the-head headsets instead; PLUS2-STX-HK is the helmet-kit pack for STX systems.Specifications Intercom type: Rugged Offroad Mono Rear-seat audio: two helmet kits Headset details: Alpha Audio speakers, a dynamic noise-cancelling mic, and peel-and-stick speaker installation inside your own helmets Cables: two 16-foot intercom cables to reach the rear seats Expands a 2-place Rugged intercom system to 4-place Includes two helmet kits and two 16-foot intercom cables. Sold as a complete two-seat expansion pack.