Riedel, "O" Series Chardonnay Wine Glasses. Pay for 6 Get 8 Boxed Sets Chardonnay Wine. So what is "O"? Riedel "O" is the new innovative take on the wine tumbler. In short: "O" is the ideal glass for every day use and for every occasion. It is fun, feels good to hold, looks trendy and it works! The designs of "O" are based on the benchmark shapes of Riedel Vinum. For the first time in glass history the design parameters such as shape of tumbler, size and diameter of rim,