Best way to connect this small amp directly to a 12V battery?

I have this 12V 18Ah battery: http://ift.tt/1FAEaJt

I'm looking at getting this small bluetooth amp: http://ift.tt/1JchC0H

What will I need between the two to power this amp directly off the 12V battery? I would assume that the battery won't always be 12V and so some kind of adapter would be necessary? Thoughts?

Thanks for the help!

Submitted May 01, 2015 at 12:12AM by TheRealBigLou http://ift.tt/1JchzSo