YONEX Mebius 2000, Blue (Suitable temperature: 12-23 degrees Celsius) Made of nylon Set of 4, 6 shuttlecocks per tube Total: 24 shuttlecocks The feathers are damaged, and there is some wobble in the flight. I don't think they can be used for games, but they can be used without problems for knock practice, physical education classes, or children's groups. I myself have been using water-fowl feather shuttlecocks for many years, but you can practice well with nylon ones, and they seem to be more durable than water-fowl feathers. The suitable temperature is said to be 12-23°C, but I was able to use these shuttlecocks without any problems even in the winter temperatures of Nagano Prefecture. I am also selling the green version (suitable temperature: 22-33°C) for summer. I will offer a discount if you purchase a set. Please feel free to contact me if you have any questions.