Thanks! Have the 10 speed Di2. Downshifting is fine-Upshifting from the 11 cog is sloppy. (Fairwheel was upfront about letting me know that this cassette would not measure up to DA shifting standards.) Barely any ramping compared to DA-if it had comparable ramping my guess is that the aluminum would quickly disintegrate) But my interest was in: 1) saving weight-the cassette pictured is an 11/28 and weighs 113 grams with lock nut and free hub spacer; and 2) using it for a climbing time trail and an ascent of Whiteface Mountain-during which I’ll be in the 39 and 21, 24,28-not much of a cross over therefore no sloppy shifts.