The FSU12A is a flow detection switch designed for use in liquid flow systems, featuring a moving magnet and fixed reed switch mechanism with low flow restriction. It operates at pressures up to 10 bar and temperatures from -20°C to +85°C (-4°F to +185°F), with a 1/2" NPT thread connection and 10" (25 cm) PVC-insulated cable. The switch has a contact form of normally open (N/O) with no flow, maximum switching power of 25 VA, and maximum switching current of 0.6 A at 240 V AC or 120 V DC. The FSU12A must operate at 0.53 US gal/min (2.0 liters/min) flow rate and must release at 0.08 US gal/min (0.3 liters/min), making it suitable for liquid flow monitoring applications in HVAC systems, water treatment, and industrial process control where reliable flow detection is required.