The new cosmetics of the S-Series looks good in nearly any car and their shallow mounting design allows for easy installation in a wide range of door panels. As well, their high-efficiency design can run off of the power from the factory or Alpine head unit, resulting in an easy system improvement for any vehicle. CEA-2031 Speaker rating: 45W maximum RMS, 140W peak power handling, nominal impedance 4Ω 4" 2-way speakers carbon fiber-reinforced plastic woofer cone with specialized rubber surround 3/4" silk dome tweeter frequency response: 97-22,000 Hz grills not included warranty: 1 year