It is important to understand the different IP ratings when it comes to Marine lighting.  Some are rating for interior use and some are rated for outside or exterior. Even at some of the higher rating i.e. IP 68; you still should submerge this lighting. As such, the second digit in a typical IP code indicates a precise level of protection against moisture ingress under specific test scenarios. The ratings widely accepted as 'waterproof' for most general purposes are IP65, IP66 and IP67.