The Yonex Mavis 2000 shuttlecocks feature the innovative Wing Rib technology which provides flight performance that imitates feather shuttlecocks. The Mavis 2000 are constructed form Nylon & natural cork, & are five times more durable than the ordinary shuttlecocks. Their outstanding performance & durability combined with cost effectiveness make them ideal for training & tournaments. The pack consists of 25 dozen Yonex Mavis 2000 shuttlecocks.