Help soothe and calm your new puppy with the melodic vibration of a mother’s heartbeat. The ingenious design of the Mother’s Heartbeat Puppy Pillows create the soothing feel and sound of a maternal heartbeat. Included with each pillow is a heartbeat device. Heartbeat device installs into pillow’s zippered pocket. Batteries included. Based on estimated heartbeats of the breed of the parents and puppy/kitten. Uses 2 AAA batteries - included Small breed, up to 20 lbs. Perfect for crate training; helps adverse behavior such as barking or whining Soothe and calm your new puppy with the melodic vibration of their mother’s heartbeat Mother's heartbeat helps puppies transition to their new home and reduces anxiety and stress