RE Audio TW20 1-Inch Soft Dome Tweeters - Set of 2 Nominal Diameter - 1"(25mm), Nominal Impedance - 4 Ohm Frequency Response - 1,500-20,000Hz  2dB, Sensitivity - 92dB Power Handling - 150W[Max]/50W(RMS) Highest Grade Neodymium Magnet, Low-Viscosity Ferro-Fluid Cooling, Pure Copper Voice Coil Wire Mounting Diameter - 1.73"(44mm), Mounting Depth - 0.95"(24mm)