I recently brought a subwoofer thought nothing of it, then brought a new car and am keepin the standard head unit in ffor the oem look! But when looking for a good price to put the sub up for sale there is not alot of information about it

It is a earthquake of San Francisco 10" subwoofer, must be american, and I have only found they are early to mid 90's and are quite hard to get hold of. There's a few numbers on the sub but nothing referring to the power of it. Only the typical "4 ohm".

any information at all would be very appreciated!