The CAP CER 390PF 3KV X7R 1808 is a ceramic capacitor with specific characteristics. It has a capacitance of 390 pF, tolerance of ±20%, and can withstand voltages up to 3000V (3kV). The X7R designation indicates its temperature coefficient range, making it suitable for various applications. This component is metrically measured as 1808, which corresponds to other designations like 4520.