The FLK-IRR1-SOL is a solar irradiance meter designed to simplify the installation, commissioning, and troubleshooting of photovoltaic arrays. It features a high-precision mono-crystalline solar sensor capable of measuring instantaneous irradiance up to 1400 W/m² with ±(5% + 5 Digit) accuracy and 1 W/m² resolution. The device includes a built-in temperature sensor (measuring range -30°C to 100°C with ±1°C to ±2°C accuracy), an integrated compass (0° to 360° with ±7° accuracy), and an inclination sensor (-90° to +90° with ±1.5° to ±3.5° accuracy depending on angle range) to measure roof orientation and PV panel tilt. The rugged, compact design (150 x 80 x 35 mm, 231 g) operates on 4 AA alkaline batteries with approximately 50 hours of battery life, and features an IP40 protection rating with an easy-to-read LCD display. The FLK-IRR1-SOL is ideal for photovoltaic system design, surveying, performance measurement, and diagnostics, meeting IEC 62446-1 requirements for testing and maintaining solar installations.