Jewel
It is spectacular how cool it is
Very nice cassette, very light, smooth and fast shifting BUT the colour fades very quickly and the cassette is no more solid than a GX so unless you have a lot of money the interest is very limited... Otherwise mantel delivery and price top!
Bought this to upgrade my Santa Cruz from a 11 speed set up. Mating it to a X01 rear mech and XX1 shifter. Shifts beautifully! Its been an expensiveness upgrade but definitely happy about it. Bought a rainbow / oil slick chain to go with it - make sure you connect the link the right way as I had slipping problems.