DS18 HYDRO MP4TP/BK 4″ Marine Water Resistant Wakeboard Tower Speakers 300 Watts – Black DS18’s new NXL-4TP 4 inch tower pods are truly an amazing effort to upgrade the durability of roughly used tower speakers. These new pods have a completely redesigned clamping system made for rough use. These pods can be mounted on any vehicle but best shines on smaller vehicles that see a lot of vibration