Fi SSD 10" Flatwind coils, looks to be brand new, dual 1 ohm. I am thinking of purchasing an amp that makes its power at 4 ohm ( Zapco 750.2 ) and this sub, wont work. If you have a single 4 ohm sub, or a dual 2, and would like to trade for my FI SSD, let me know. I can take pictures, but she looks brand new. Got it from billabong in a trade. Let me know!