Best known for its iPhone keyboard cases, Nuu has expanded its product lineup to include Splash ($99), a waterproof Bluetooth wireless speaker. Having earned an IP55 rating, it's capable of withstanding splashes, dust, and more. It looks essentially the same as many of the Jambox-like portable wireless speakers on the market right now, offering users the choice of a silver, red, or black aluminum casing. The internal battery is rated to last for seven…