the optima batteries are sealed,dry cell
and make a big difference in the sound in a car.
if anybody dabbles in multi amp car systems, then i highly recommend them,
there is a lot of reserve there,sorry to plug optima in this forum but we know who makes some of the best(if not the best value,with quality in mind) home theater products so i think everybody should know that on the same lines they are the best for car audio batteries