Shimano Ultegra CS-RS8000/CS-HG800 (11 x) - buy at Galaxus
Amazon.com : JGbike ~180g Lightweight 11 Speed Single Piece Cassette for Road Gravel cyclecross Bike, for Shimano Dura Ace Ultegra or SRAM Red Force for Triathlon - The Best Value Cassette Available :
Shimano Ultegra Cassetta Pignoni CS-R8100 11-30/34D 12v - Taddei Store