Mint. Dual 4 ohm, sealed box ranges are .35 - .5 cubic feet. Ported ranges are .65 cubes tuned to 35hz, and 1 cubic feet tuned to 35hz.
$40 firm:
Features:
•Electrical Q Value -Qes: 0.39
•Mechanical Q Value -Qms: 4.37
•Total Speaker Q Value -Qts: 0.36
•Free Air Resonance -Fs: 21.5 Hz
•Equivalent Compliance -Vas: 75.6 liters
•One-Way, Linear Excursion -Xmax: 12 mm
•Efficiency -SPL 1W/1m: 84.7 dB SPL
•Effective Piston Area -Sd: 322 cm^2
•DC Resistance -Re: 3.2 ohm
•Nominal Impedance -Znom: Dual 4 ohm
•Thermal Power Handling -Pe: 175 W
•Force Factor -Bl: 15.4
Specifications:
•Mounting Depth - 5"
•Mounting Hole Diameter - 9.3"
•Overall Diameter - 10.9"
•Bolt Hole Circle - 10.5"
•Motor Width - 4.875"
•Motor Depth - 1.9"
•Basket Depth - 3"
•Displacement - 0.09 cu. ft.
http://reaudio.com/specs.html#sp_rex