These lights are shockproof,  waterproof and have an extremely low-energy draw. They are encased in UV-resistant epoxy and are not hot to the touch. D103 Series is 1″ OD and requires a 11/16″ hole. Starr Light Series is 1-7/8″ OD and a requires a 1-1/4″ hole. Its also underwater rated. All are 12-Volt.