Ideally suited to use with inflatable collars or caring collars to help support pets through the recovery phase post-surgery when use of a surgical collar is recommended. Calming Disks are also ideal for everyday use with your pet’s regular collar or harness to provide calming support day and night. The disk releases natural essential oil extracts, well known for their calming properties in dogs. The disk provides calming support for up to 21 days. Fits both small and large collars.