Waterproof and Wireless 

Audio Unlimited PoolPOD 900Mhz Wireless Floating Waterproof Speaker Audio Unlimited’s PoolPod wireless floating speaker allows you to enjoy your music while relaxing in a hot tub, pool or any other water environment. This fully waterproof speaker is powered by 900MHz Phase Loop Lock circuitry, which guarantees a strong, clear signal up to 150 feet away, with no line of sight limitations. The transmitter delivers a powerful signal through walls or any other obstacles in your yard. 

Works with Most of Your Current Stereo Equipment 

Just plug in your iPod, computer, stereo, MP3 player or any device that has a 3.5-millimeter or RCA output and enjoy high quality music without the hassle of running wires. Volume, powers and mood light controls are on the speaker itself. The speaker runs on 6 AA cell alkaline batteries. The transmitter can be battery powered (using 4 AA cell alkaline batteries—not included), or powered via optional AC adapter (included). 

You can pick yours from Amazon for $69.