1 inch - Exit PETP Film Diaphragm Compression Driver / 1.75 inch Voice Coil - Bolt-On Version 
Each transducer is built to exact engineering standards using innovative design concepts and materials. All components are manufactured to maximum tolerances and are subjected to a wide array of quality-assurance tests pre and post assembly. It is for these reasons that you can rely on B-52. 
Specifications
- Power Handling: 125 Watts RMS
 - Frequency Response: 800-18kHz
 - Voice Coil Diameter: 1.75"
 - Nominal Impedance: 8 Ohms
 - Magnet Structure: 35 oz
 - Weight: 6 lbs