More than just a fashion accessory, having a good collar is essential to ensure your cat can be returned to you when it gets lost. Some cat collars are also functional - fluorescent collars and reflective collars help them to be seen at night, whilst collars with bell attachments will alert birds and other wildlife to your cats location, making them a cheap and effective way to reduce wildlife hunting.
Most adult cat collars are adjustable between 20 and 30cm in length which covers most breeds and sizes of cat, kitten collars tend to be less than 20cm.