This is a CAP CER 18PF 1KV C0G/NP0 1808 capacitor with the following specifications: - Capacitance value of 18 pF - Tolerance of ±10% - Voltage rating of 1000V (or 1kV) It is classified as a Ceramic Capacitor, specifically a C0G or NP0 type. The size of this component is referred to as 1808 (or 4520 in metric notation).