Here are the specs :
Z: 8 ohms
Pavillon material : acier
screw number magnet/horns : 4
resonance frequency ( fs): 1500 Hz
Max. frequency : fx-18kHz
Rec. crossov. Fréq. (Fmax.) (12dB/oct.): 3000 Hz
Max Recommanded Amplifier : 100W/8ohms
Nominal Power : 50WAES
SPL (1W/1m): 105dB
spatial coverage (vertical/horizontal):45°/90°
voice coil diameter : 24,5 mm
magnet diameter : 80mm
mounting hole shape : 240x80mm
mounting depth : 193mm
size dimensions : 268x107mm
weight : 1,4 kg
diaphragm model : Monacor MHD-1255/VC
Somes told that J-105 can support 125W above 5Khz : really it's not sure...
That I can tell you is that driver ( MHD120 ) can support at least 65W in program material, over this I'm not sure.
In a full range system, with 95db/W/m woofer*, this compression driver can follow the woofer with 250W of power, about 117db/118db SPL ( amplifier 2x450W / EP2500 ).
*3 inch voice coil, 7 inch magnet.