2007 GT3

Just changed out a dead Interstate MTP 91 which has a larger oval shaped vent outlet which an appropriately sized sleeve fits over to attach to the vent.

Bought a Walmart MAXX H7 which has a smaller (between 3/16 - 1/4 inch diameter) round hole vent which I need to stick an adapter into. The battery didn't come with any sort of adapter/tubing.

Pepboys couldn't help. Not surprisingly, neither did Walmart.

 

Go to a dealer they will give you one for free.

 

maybe just get a piece of plastic tubing the same diameter of hole and stick it in there.
My hardware store has 2 aisles 50' long with nothing but hardware pieces and doodads of all types, nuts, fasteners etc. might find something there.

 

go to ebay enter batteryvent kit Porsche 997

one comes up for a boxster but im sure it looks like it might work