Here is what I found with a quick search, and man, they sure are proud of their stuff .... This particular description says it has a 2.5" vc's, but all the others I found say 3", which I would tend to think with a 500-2000rms power handling suggestion ....
Get that “Big Bottom” with the HIPPO Subwoofers When Massive Audio designed the “HIPPO” Series Subwoofers we had one thing we wanted out of the design. No junk for a trunk just a subwoofer with a “Big Bottom.” All three Hippo Series subwoofers 8”, 12” and 15” are truly giant works of art that can slam! These big bottomed boys use 3” over sized voice coils that hold 4000 Watts of power, extra deep diamond polished cast aluminum baskets, double stacked Strontium Magnets and Kevlar Fiber Reinforced Non-Pressed Paper Cones that has a industrial machined stitched edge right into the cone’s surround for added strength. To feed a 2013 HIPPO Massive Audio recommends 500 – 2000 RMS of raw power. You can cage a HIPPO in a sealed box as small as .375 cub. Ft for Hippo 8, 1 cub. Ft for the 12” and only 2 cub ft for the 15” or you can let them relax in a ported box for even more of that “Big Bottom ”. Massive Audio “HIPPO” Series is Big, Bad and Beautiful”.
FEATURES:
Heavy Duty, Rugged Industrial Textured Cast Aluminum Basket
High Energy Double Stack Strontium Magnet Structure
Dual Impedance Black Anodized 2.5” Voice Coil Former with Kevlar Spunlace
Kevlar Fiber Reinforced Non-Pressed Paper Cone with Industrial Textured Finish
Stitched Edge to the Cone’s Edge for Added Strength
Over Sized Mirror Image Dual Poly / Nomex Spiders
Black Anodized One Piece Pole-Plate for Added Motor Force
Heavy Duty Direct Input Wires Connection to Voice Coils
Reinforced Fiberglass Woven Dust cap for High Power Applications
Custom Tooled Rubber Gasket and Magnet Boot
SPECIFICATIONS:
Size 12"
Peak Watts 2000
RMS Watts 4000
Cone Non-Pressed Paper
Voice Coil 3" Dual 2 Ohm
Surround Tall and Narrow Foam
Magnet 320oz Strontium
Terminals Heavy Duty Direct Input Wires Connection
Basket Cast Aluminum
Tinsel Leads Heavy Duty Triple
X-Max 15mm peak to peak
SPL 95.99dB
Ported Box 14"H x 16"D x 20"W (Round Port 2 4" x 12")
Sealed Box 1.58 ft3