USW300 300W Underseat Subwoofer Active Car Subwoofer with Built in Amplifier. Rated 5 out of 5 by us. Rich powerful base – With a built in amplifier, max output of 300 W and 130 W RMS, the In Phase USW300 is a true pocket powerhouse of audio performance. Aluminium coned subwoofer – Aluminium Cones are light in weight and can be really stiff, but they are really robust cones that rarely go wrong. This sub has a damping material built into its cone and spider to ensure a rattle-free performance and deep bass. Heavy duty durable construction – Die Cast Aluminium Chassis – no plastic structure here. The metal body is part of a secure and rigid structure, no flexing body when the unit is in full power, this also helps with bass output. Compact and discrete – Allowing to install the USW300 anywhere within vehicles Boot, Undersea, behind seat and foot wells. Need that little extra bass? Haven’t got much space? This little beast was designed as direct competition to the Kenwood KSC-SW11 and the Pioneer TS-W130EA. Everything about this sub is superior, the structure, cone material, the amplification and the robustness. The key thing about the In Phase USW 300 is the performance, the little active woofer really packs a punch, the bass response is amazing, you really do get SUB Bass from it. It’s extremely responsive so the music has a completely different sound once added to the car. That’s what is missing from its competitors, responsiveness. They simply do not respond as well to frequency changes or music types. Our shop cares about your experience, we will be at your complete disposal for all your doubts!