The Gray Key is the normal Ignition key; the Red Key is the Master Key that won't let you operate or open anything, but is essential for adding keys to the DESS of 2013 & earlier Spyders. :thumbup:
Those Red Keys are pretty scarce now, but are only sought after by owners of 2013 & earlier bikes who want/need to add keysto their security systems, and to do that they still MUST have a working Grey Key.... and the adding process isn't exactly 'hard', but it is a bit of a saga that MUST be completed properly or you'll have key issues from there on - quite a few seem to find it difficult to complete & mess it up! :banghead:
But if your Bike is a 2018 F3 as it appears from your other posts (btw, you really should add that info to your sig line so people don't hafta guess or ask - it's always handy to know when answering questions...

) the Red Key is useless to you - maybe you could sell/trade/give it to someone who services/works on earlier Spyders, or the owner of a 2013 or earlier who's trying to add keys?! :dontknow: