The screws and such for the cord clamp are brass or stainless. They have a gland where the cord enters the clamping section of the plug, to exclude "most" of the water and foam. The plastic is a type that won't get pale and brittle with constant chemical cleaning and washdown. They often feature a "lid" or "plug" or sorts to seal up the business end when the equipment is unplugged.Marine grade?
Whats the difference between ordinary devices?