Depth: 2.9", 73.6mm Weight: 1.6pound, 727g Replacement Driver APT:50 Throat Size 1", 25.4mm Nominal Impedance. 8 ohms Power Rating. 35W @ 3.5kHz Free Air Resonance 2.1kHz Usable Frequency Range 3.5Hz-20kHz Sensitivity: 104.7dB (1W/1m across 3.5kHz-20kHz) Magnet Weight 7.75oz, 0.22kg Voice Coil Diameter 1" / 25.4mm THIELE & SMALL PARAMETERS DC Resistance (Re) 6.3 Coil Inductance (Le) 1.5mH MOUNTING INFO Overall Diameter 2.75", 70mm Mounting Holes Diameter. Mounting Holes B.C.D. ~ Mounting Thread Use Apt Horn or Adaptor Depth 2.53", 64.3mm Weight 1.65 pound, 0.75 kg MATERIALS OF CONSTRUCTION Diaphragm Material Phenolic Magnet Composition Ferrite