Audio Unlimited Add-On Premium 900MHz Wireless Rock Speaker (Sandstone) Fully compatible with all Audio Unlimited products Add additional Audio Unlimited speaker to enhance your listening experience, cover large areas or create a multi-room sound system Compact & portable with a stylized design (13H x 10W) - 5.25 PP cone w/rubber edge Woofer2 Mylar cone Tweeter20 Watt RMS Output15V DC Transformer Speaker can either be battery powered (using included 12V AH rechargeable battery) or, using the included AC adapter Weatherproof for outdoor listening