The Rugged Radios PLUS2-BTU rear-seat expansion kit takes a two-person Rugged intercom setup to four seats. This configuration pairs Offroad Mono cabling with Ultimate behind-the-head (BTH) headsets for the two rear seats, with 16 ft intercom cables that reach the back of the machine.What the Ultimate BTH headset bringsThe Ultimate behind-the-head headset features a carbon-fiber-style finish, an M101 dynamic noise-cancelling mic, hard-wired cabling, large gel ear seals with cloth ear covers, and on-ear volume control — comfortable rear-seat audio without a helmet.CompatibilityThis Offroad Mono configuration is for Rugged MONO intercom systems. The PLUS2 family also offers STX Stereo configurations for STX Stereo high-fidelity intercoms, plus helmet-kit versions — pick the configuration that matches your front-seat system.Specifications Expands a two-seat Rugged intercom system to four seats Configuration: Offroad Mono cabling + Ultimate behind-the-head headsets 16 ft intercom cables reach the rear seats Ultimate BTH: M101 noise-cancelling mic, gel ear seals, volume control Includes the rear-seat headsets and 16 ft intercom cables for two rear positions.