From the http://www.jlaudio.com website

Nominal Diameter: 12 inches (300 mm)
Continuous Power Handling: 300 Watts
Voice Coil: 2.25" diameter, 4-layer, Kapton former
Available Configurations: Dual 2 ohm, Dual 4 ohm or Dual 6 ohm
Xmax (one-way, linear): 0.46"-0.51" (11.7-13.0 mm) depending on specific model
Sealed Enclosure Range: 1.00-1.50 cu.ft. (28.3-42.0 liters)
Ported Enclosure Range: 2.00-3.00 cu.ft. (57.0-85.0 liters)
VRC™ Technology: YES
Elevated Frame Technology: YES