Millennia Spa Stereo Speakers - 3.5" - Marine Grade Outdoor for Hot Tub, Boat, ATV, Motorcycle, Golf Cart - Pair Set of (2) All weather - marine grade speakers 3.75" round (outside diameter) - uses 3" mounting hole 50 watt rating @ 4 ohms Full range waterproof speakers for spas, motorcycles, boats, ATV Easy installation - Amazing Sound Quality (check reviews)