The One Ball Battery Indicator The 1-ball push in model is by far our most popular model. The 1-ball model is generally used for automotive battery applications but is not limited to this category. As displayed below, it will provide a bright green indication if the battery is charged, a dark indication if the battery is discharged, and a clear and bright indication if the electrolyte level is low. A one ball battery indicator displays three distinct stages of a battery's condition. Item Name C Series Item NO. Size(mm)Head diameter Head thickness Packing thickness Screw diameter Screw pitch Length Plastic head with screw/straight Pole/1 ball C201 Ø20 4 2 M16 2 40/41/45/50/54/55/58/60/62/65/68/70/73/77C202 Ø20 4 2 M15 1.5 C203 Ø23 3 2.6 M16 2 C204 Ø23 3 2.6 M15 1.5 It is noticed that we could make a new mold according to the requirements of customer.