Additional transmitter for LunaSafe Water Safety System. Transmitter has approximatley 100ft line of sight wireless range. Comes with locking wriststrap for children, velcro strap for pets, and carabiner for life vests. Battery last for approximately 5 years. WARNING: This system is not a life saving system and is not intended to be solely relied upon by user for supervising an area of safety concern. This system is meant to supplement active human supervision of minors. This system is subject to technology shortfalls such as (but not limited to) interruptions in electrical power, battery failure, or radio interference. Always make sure minors are properly supervised by an adult.