The ZenCollar is a premium protective collar that is designed to protect your pet from reaching injuries, rashes, or post surgery wounds. The ZenCollar has an inflatable inner bladder made of a plastic vinyl that is inflated through a two-way air valve much like a beach ball. Once inflated, the size and thickness of the ZenCollar function as a soft deterrent. The inner bladder is protected by a pliable plastic outer jacket lined with a durable canvas material to resist bites and scratches. The ZenCollar is held in place by inserting the pet's everyday collar through the the ZenCollar's three inner rings. The velcro strap should be placed at the back of the neck and then adjusted for a perfect fit. While wearing the ZenCollar, pets are able to eat, sleep and play at ease while staying protected. To prevent another animal from biting the patient's collar, simply rub with bitter apple or ammonia. The ZenCollar is machine washable or can be washed with anti-bacterial soap and laid flat to dry. Always monitor a pet post-surgery to ensure that the collar is working properly. Some pets may be able to maneuver around any collar. Sizing: Measure the length of your pets collar to find the right fit. If your pets collar is right between two sizes, its best to pick the larger size. Recommend Fit: 13" - 18"