The yellow top is a dual purpose starting/deep cycle battery. They actually have a lower cranking amps than the red top, but a longer amp/hour rating. They're also better for deep cycle use, such as running a winch, snowplow, RV use, or stereo systems. Unless you have alot of accessories that require operation without the engine running, get the red top. You'll also see a blue top. That's a marine use battery, pretty much strictly deep cycle. I have also seen an orange top that was 6 volt for ag use, but that was several years ago, and isn't listed in the catalog.
