a: Electrolyte level: The final distance between the electrolyte level and the cell opening after the Fill Plug stops the inflow of water.
b: Float length: The distance between washer and the bottom of the float.
c: Min. required distance between cell opening and plates (or moss shield):
The minimum distance that must exist between the battery's cell opening and its plates or moss shield is the “Float length” plus 5 mm (1/5 inch).