Dayton Audio DAEX32EP-4 Thruster 32mm Exciter 40W 4 Ohm Robust, heavy-duty design with a 32 mm voice coil attached to a steel spider Pre-applied 3M&#8482; VHB&#8482; adhesive for quick, secure installation Rare-earth neodymium motor and a proprietary two-layer voice coil 4-ohm impedance for use with small, Class D amplifiers 40 watt RMS power handling for high output