3 levels of volume adjustment: High or Medium or Low. 38 ringtones for choosing. It can be successfully used for your home, office, store, hotel or other buildings. Ideal for alerting business owners who are working in the back or out of sight when customers enter the store. It can also be used as a signal when a pet is ready to enter or exit. Applications: entry alert, burglar alarm, corridor alarm, critter detector, car alarm (indoor), warehouse monitor, closet alarm power supply, garage and tool shed monitor, mailbox sensor, front door or walkway detection.