The jbl gto series high fidelity automotive speakers feature innovative technologies that weve engineered for the environment and for the conditions in todays cars to help them deliver exceptional sound using carbon injected plus one us patent no 7 548 631 woofer cones fiberglass reinforced plastic frp frames butyl rubber surrounds and fabric tweeter diaphragms the gto series automotive speakers are the ideal upgrade to any cars audio system gto series speakers including compon