New Key FOB Remote Replacement Case, Blade, Battery?
 

I just purchased one of these on Ebay and I'm a bit unsure what I will have to do with it when it arrives in the mail?

PORSCHE 996, BOXSTER S, 911 NEW KEY FOB REMOTE REPLACEMENT CASE, BLADE, BATTERY | eBay

Its a repair kit, not a spare key as it contains no chip.
You transfer the chip in your key and clip into this new body. You could also get the blank blade cut by a locksmith or fit your existing key.
It takes minutes to swap, you just need a very fine flat blade screwdriver to prize the button cover off you existing key.

The porsche keys fail because of the micro switches stick or wear, this kit does not include replacements. If this is the case, using electrical cleaner on the switch helps.

Make sure you refit the rubber gasket when you put the chip in the new plastic case.

Cheers

Thanks
This means I will lose the Porsche logo on my original key
Oh well