M size - for mid size cats of 9-11 pounds (4-5 kg). L size - for bigger cats 12-15 pounds (6-7 kg). Xl size - for big cats 16-20 pounds (8-9 kg).Xxl size - for big cats 21-24 pounds (9-11 kg). You can easily wash the felted bed by hands or with washing machine (wool option) and detergents for wool. In order to keep nice shape of bed, after washing, recommended to insert few dry towels inside the bed. Please leave the bed to dry 4-8 hours and continue drying with removed towels. If you have any questions or wishes, please don't hesitate to contact with me. This item is made of ecofriendly wool.