ALPINE Compact 4-channel Digital Power Amplifier KTP-445UJ Rated output: 45W  4ch (4) / maximum output: 80W  4ch (4) / BTL connection: 90W  2ch (4) Wiring from the engine room unnecessary / RCA input speaker code input Compatible with both / high-pass filter and gain control Rated output: 45W  4ch (4) / maximum output: 80W  4ch (4) / BTL connection: 90W  2ch (4) Power supply wiring  RCA cable (2m) included. Japanese manual download site URL:http://products.alpine.co.jp/om/owner/product?P1=4485