It's a Polk Audio 12 I bought to tide me over until I got some new subs. What kind of sub is it? Power ratings and so forth?

 

Polk EX Series II

Power - 150rms/400peak
Frequency Range - 20-500
Sensitivity - 93dB
Sealed Box - 0.95cu.ft.
Ported Box - 1.25cu.ft.
Retail $129.99usd

From ~'99 era and it's a low-mid level sub designed to work in small enclosures.