The FNIRSI S1 Smart Digital Multimeter is a compact and intelligent measuring instrument designed for professionals, engineers, electricians, students, and DIY enthusiasts. Featuring a large full-color digital display, True RMS measurement, and automatic function identification, it delivers fast, accurate, and reliable electrical measurements. The S1 supports AC/DC voltage measurement, resistance, capacitance, frequency, continuity, diode testing, and Non-Contact Voltage (NCV) detection.  Its intelligent anti-burn protection enhances safety, while the built-in rechargeable battery, flashlight, and data hold function make it ideal for field service, industrial maintenance, automotive diagnostics, and home electrical repairs. With its slim, ergonomic design and easy-to-read display, the FNIRSI S1 offers a convenient and efficient solution for everyday electrical testing.