The McDonnell Miller FS7-4SWJ Flow Switch is designed for 1-1/4" BST connections, providing reliable flow detection in various systems. This switch is constructed from durable materials, ensuring longevity and performance in demanding environments. It features a compact design that allows for easy installation and integration into existing systems. The FS7-4SWJ is ideal for HVAC applications, ensuring optimal flow rates and system efficiency. With its precise activation point, this flow switch helps prevent system failures and enhances operational safety.