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.