This is a Circuit Shop Audio Diarphagm made to JBL specs.  It fits  JBL 2412, 2412H, 2412H-1 Drivers.  This diarphagm was used in many differant JBL models.  Specs: Overall Diameter: 2.67" * Voice Coil Diameter - 0.98" * DCR - 4.2 ohm * Impedance - 8 ohm.  Circuit Shop Audio diaphragms are gaurenteed to fit perfectly and sound just like the original. Don't settle for cheap "aftermarket" diaphragms.