Battery Terminal Types
On your battery, you'll see two prongs sticking out from the top that connect to wires inside the speaker. These are called "terminals." There are two types of terminal connection possibilities that can come with a 12V rechargeable sealed lead-acid battery: F1 and F2.
The vast majority of sealed lead-acid batteries found in ION Audio products will require an F2 terminal type. These are slightly larger than the F1 terminal type.
If you purchase a battery with the slimmer F1-type battery connection terminals, it can still be used as long as all the other specs of the battery are correct. To connect the battery you will simply need "F1 to F2 Step Up Adapters", these are inexpensive and available from hardware stores. These adapters slip over the slimmer F1 terminals and make them slightly wider, allowing for F2-type terminal connection cables to attach correctly.
If you are not sure what battery is required for your ION Audio speaker, please see here: What battery does my ION speaker use?