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