This is a Bulcan Bell water rescue device which is equipment used in water rescue operations, particularly for quick deployment in situations where someone is in distress in the water.

This Bulcan Bell allows rescuers to assist individuals in water without having to enter the water themselves, which is particularly useful in dangerous or difficult conditions. 

This type of equipment is part of standard rescue gear for lifeguards, water rescue teams, and other emergency responders who need to act quickly and efficiently in water-based emergencies.