RSF84YP is a compact external tank-mounted level switch designed for mounting through tank walls via 1/2" NPT thread without requiring internal tank access. The switch is constructed from polypropylene material with WRAS approval and features a temperature operating range of -20°C to +100°C (-4°F to +212°F), making it suitable for diesel generators, hydraulic oil, and gearbox oil level monitoring. It provides a maximum switching power of 25VA with a maximum switching voltage of 240V AC or 120V DC, and a maximum switching current of 0.6A for resistive loads. The switch can be configured for either make-on-rise (N/O) or make-on-fall (N/C) action by rotating through 180°, and features an M12 circular connector socket with switch contacts on pins 1 and 2. Typical applications include industrial fluid level monitoring in harsh environments where compact external mounting and reliable switching performance are required.