PC680 is a great battery. I have one in my other toy that is 11.25:1 compression ratio V8 and spins the starter just fine. But its 15lbs weight is old skool. The new trend is lithium coming in at 5lbs and fits in the glove box.
You can get the pc680 at Batteries Plus. They keep them in stock around here. The cool mounts are an on-line only thing.
I got my battery and mount here before I knew Batteries Plus had them.
Odyssey Batteries