This is a high-quality ceramic capacitor with the designation CAP CER 51PF 1KV C0G/NP0 1111. It has a capacitance value of 51 pF ±1 and can withstand voltages of up to 1000V (1kV). The capacitor is made from a C0G, NP0 (1B) material and is packaged in a 2828 metric configuration with the marking 1111.