Kel-Tec RDB 5.56mm NATO 16in Black Semi Automatic Modern Sporting Rifle - 20+1 Rounds - The RDB Defender is the result of taking the RDB and the RDB Survival and mashing them up to forge the perfect 5.56, light-duty, tactical bullpup. Its lightweight, comes standard with an aluminum, M-LOK handguard, collapsable stock and 16 pencil profile barrel. Defend your property, your community and your homeland with the most tactically versatile bullpup on the market with the RDB Defender.