The sound can be set for 15 or 30 minutes, depending on your baby's needs. Simply twist the top section to select the time you want. The Baby Shusher is wireless and portable, so it go anywhere baby goes. Each device comes with a handy wrist strap making it easier to carry or tether to the carseat. Quickly calms fussy babies with rhythmic “shush” sound Adjustable volume and timer options for 15 or 30 minutes. Detachable wrist strap for babies on the go. Nontoxic and skin-safe with no BPAs, latex, lead or phthalates. Arrives ready to use with 2 AA batteries installed.