It actually is the factory vent tube assembly to vent the battery gases. I bought an aftermarket battery and I am here actually looking for information on exactly how do I install it. I have the 4 inch thick factory dealer Allante book and it doesn’t even show a diagram in there. From what I can gather it’s only usable with the exact fit factory battery I can’t figure it out but that’s what it is that solves the mystery. The point maybe kind of moot now with the newer batteries that don’t have the vented caps. If I find any more clarifying information I will come back and post but this thread is probably so old you guys have sold the cars who knows...

 

Ha ha ha - Optima is NOT a GEL Battery but AGM Ha ha ha!!!!

Best GEL batteries are Sonnenschein Dry Fit

and MK batteries are the best for Allantes Allante battery tray is short
MK has a 73 ah battery higher than normal and rather short