Wow! This cassette from Ceradure, based in the Netherlands, is crazy, crazy light. It tips the scales at 84 grams compared to 155 grams for a SRAM Red cassette. They also manufacture a stem made from magnesium. Both the stem and cassette are the lightest available, and according to a review on Bike Radar, the cassette performs very well. I am hoping to be able to present my impressions of both these pieces in the future.