This is a ceramic capacitor with the designation CAP CER 12PF 2KV C0G/NP0 1808. It has a capacitance of 12 pF and operates within a tolerance of ±5%. The capacitor can withstand a maximum voltage of 2000V, or 2kV, making it suitable for high-voltage applications. It is classified as a C0G or NP0 type ceramic capacitor with a metric size designation of 1808 (4520).