When purchasing boat speakers, you must prioritize IPX (Ingress Protection) ratings, specifically IPX6 or IPX7, to ensure resistance against high-pressure water jets or temporary immersion. Additionally, verify that the speakers feature UV-stabilized plastic housings and salt-spray resistant grilles (tested under ASTM B117 standards) to prevent corrosion and yellowing in harsh maritime environments. For audio performance, look for a high sensitivity rating (88dB or higher) to ensure clear sound over engine noise and wind.