This Diaphragm Fits for JBL 2446, 2446J, 2447, 2447J, 2450, 2450J, 2451, 2451J, 2451SLJ, 2452, 2452J driver / horn. Overall Diaphragm Diameter: 5" (127mm) Voice Coil Diameter:  3.91" (99.2mm) Diaphragm Thickness:0.05mm Diaphragm Height:18.4mm Nominal Impedance:  16 ohms DC Impedance :8-12.5ohms 2pcs