Amazon.com: 1" Audio Car Tweeter Speaker - Aluminum Die-Cast Frame, 300 Watt Peak, 2k-20kHz Frequency Response, 4 to 8 Ohm, Heavy Duty 30 oz. Magnet Structure - 1 Tweeter - Pyramid TW44,
Amazon.co.jp: Sound Storm EV4 X 1000 Evolution 1000 – Watt Full Range, Class A/B 2 to 8 Ohm Stable 4 Channel Amplifier with Remote Subwoofer Level Control by Sound Storm Laboratories : Automotive