5 Size Basically For Cats and small to medium dogs Between 4-38 Pounds: Size2 (for young kitten and rabbits):7.87-9.054.92; Size3 (for cats and tiny dogs):9.44-10.625.70; Size4 (for cats and small dogs):11.02-12.206.10; Size5(for small and medium dogs):12.59-14.177.08;Size6 (for medium dogs below 40 pounds):14.57-16.148.26. Please measure your pets neck before purchase. For the pets with bigger head, you can choose one size bigger.<br>Breathable Mesh MaterialFar more breathable and comfortable mesh material than traditional plastic Elizabethan Collar.<br>Lengthened Closure: Ajustable closure design enables dogs and cats cone easy to wear and adjust the tightness slightly. You can ajust it according to your pets sizes.<br>Lightweight & SoftThese E-collars are light and soft, pets never feel unblance because of the extra burden. The cones seem do not exist.<br>Specially Designed Edges: The edges are soft and comfortable, it will protect your pets necks, skin and hair. They can be used in many situations, like medical treatment, hair care, shower clean, after-care.