As I recall there are 2 different sizes that will fit. I was searching last spring with the intent of buying the highest rated AGM battery that I could find. I could not find one in the larger size so bought a replacement for the stock size. I bought an AGM from Batteries Plus, X2 Power brand I think.What’s the best and highest capacity amp battery we can buy for or JLs? Any one here gone through replacing there OEM accessory battery with a high quality one, be whether it’s a agm or conventional.