Kinivo ZX220 Portable Twin Speakers with Rechargeable battery ERCD - Expansive Resonator Construction Design to give the best low frequency output Compatibility: all iPods, iPhones, MP3 players, Blu-ray/DVD/CD players, computers, and laptops with 3.5 mm audio port Full-bodied, stereo sound Portable compact size with long-lasting internal chargeable battery Magnetic base for quick and convenient storage of speakers