F1 and F2 battery terminals
The F1 and F2 are a type of connector that is located on the top of an SLA battery. F1 terminals are .187 inch wide and F2 terminals are .250 inch wide. The contact towards the end narrows for both battery terminals. Most emergency light applications use a F1 terminal and most emergency power backup (UPS) applications use F2 terminals.
The F1 battery terminal is 0.187″ wide. Sometimes the application needs a larger terminal. In these cases you may want to get an adapter to attach to the F1 and make it compatible with F2 connectors.
The F2 battery terminal is 0.25″ wide. The difference between the F1 and the F2 is only 1/16″. This may seem insignificant but your application may not run if you choose the wrong terminal.