I found out the battery on my Gravely was a strange one. Only place in town that had them was Central Battery.
It is 7x9 on top and 7 inches high. Most 12v batteries are about 7 1/2 inches min. height.
It also has the hold down shelf down near the bottom and at the 9 inch ends. Most 12v batteries have the hold down shelf along the long side.
Batteries Plus had one that probably would have fit, but it was about $75. The Central Battery one was a virtual dead ringer fit and was about $50.
Ralph