Bandanas made of 100% Cotton fabric (light, comfortable and hypoallergenic). They can be washed by hand or in the machine (recommended at temperatures up to 30º degrees) and ironed. To know the ideal size, just measure your dog's neck and see what size it fits. If the size is very close to the maximum limits of one of the sizes, we advise you to purchase the size above. Do you need help or did you have any doubts? Contact us to help:)