Here are some pics of the battery. It is well built.Here is the one I have. Check it out at bikebatts.com. Lately when I have checked they have been out of stock though. They may be able to direct you to someone who has them if they do not. I have had it two years with no issues and no having to take off the seat to check the fluid levels.
Powersports Batteries at 1-888-561-7100.
Here's info on the battery I believe is the one to get:
YB12AL-A2 BikeBatts AGM, Sealed Activated Maintenance Free Motorcycle
Model: YB12AL-A2 AGM
Type: AGM Maintenance Free
Amps: 12.00 Amps
Size: 134.00mm x 80.00mm x 161.00mm
Weight: 9.50 lbs