This Horn Compression Driver is designed to be fitted to a suitable horn flare with a 1⅜" screw thread. Titanium Diaphragm, Kapton Bobbin and a Copper Clad Aluminium Voice Coil. The driver must be connected via a suitable audio filter or crossover. For optimum performance and reliability the compression driver should be supported in the cabinet, to relieve the weight on the horn flare.