Waterproof Design: The Marine Stereo Receiver has been IPX6 rated. One Pair (Total of 2 PCS) 4 speakers have been outfitted with the latest weatherproofing techniques. Bluetooth: Built-in Bluetooth technology allows you to instantly play music via your smart devices– quickly and easily! (like iPhone, android, smartphones, iPad etc). This stereo has no CD player, but has the ability to stream your audio wirelessly. Installation Dimensions: The of this speaker pair in white makes them easy to install with 4 inch standard size. RECEIVER SPECS – Dimensions Mounting Hole 3.1″ and Dimension Mounting Depth 1.6″. SPEAKER SPECS – The outside facial Diameter is 4.88″ with Mounting Hole Diameter: 3.8″, and Mounting Depth:1.37. If you receive an item and it doesn’t work properly or you don’t like it because of any reason at all. Please wait for the result of cancellation. The order will be processed and completed by automatic warehouse system within 5 minutes. Sending direct message to cancel the order is not allowed for every case. For the return case.