I just picked up the 3T bailout cassette from Excel Sports for $242. Why do I want this you might ask. First off my gravel bike is 1x, I love 1x for offroad so a front derailleur is not going to be on the bike ever. I currently use a 38t chainring with a 10-42 Sram cassette. Works great a for all around riding. However I am going to be riding the entire C&O canal next month (184 miles). It is pretty flat for the most part and while doing some training rides I have found that I spend about 90% of the ride is either the 14 or 16 cog. Ideally I want to have some closer spaced gears, so I picked up the bailout and will be running a 32t up front. This will keep me in the 12-13-15 range of the cassette, which will make it easy to keep at a good cadence. Even with the 32t up front, the 9t cog in back should give me all the top end I will need for this ride. The 32t bailout cog probably won't be used, but I will be staying in Harpers Ferry on the ride, and I believe I'll have to ride up a pretty big hill there, so it might come in handy there. I just got it today. The first dissapointment was to see that the actual cassette is not the same as the prototype. The prototype actually won some design award, but I suppose it was too difficult or expensive to make. The actual cassette is made by E13, so instead of the prototype's 1 piece design it is 2 piece like E13 cassettes. I have a 9-46 E13 cassette, and its okay, the shifting quality is not as good as SRAM or Shimano. The weight of the cassette is 217g, so its pretty light. I'll get it mounted up tonight and try to get some miles on it this week to see how it shifts.