Which cassette should I buy?

Good morning,

I have a bike : Trek Emonda SL 5 Shimano 105 11V 700 that is using a Shimano 105 R7000, 11-30 teeths, 11 speed.

I would like to buy the WAHOO KICKR CORE with a pre-installed casette but i’m not sure about which one I have to take : a 11 speed or 12 speed ? Since that my cassette is 11-30 teeths but on wahoo website, it say that it is related to a 12 speed cassette :

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Thank for your help !

If it was me, I’d go the no cassette option, then buy a cassette identical to what’s on the bike and fit that on the trainer myself

You must use an 11 speed cassette with your 11 speed drivetrain. You may as well order the one with the 11 speed cassette even if you want some other gearing. The 11-28 cassette will work with your bike. Derailleur adjustment is often needed regardless of which cassette you use.

The 11-28 11sp cassette will work for you. It just means that the easiest gear has 28 teeth instead of the 30 on your bike but that won’t affect anything mechanically related with your setup.