The part number is CAP CER 820PF 4KV X7R 1812. This refers to a ceramic capacitor with specific characteristics: it has an capacitance of 820 pF, tolerance of ±5%, and voltage rating of 4000V (4kV). The X7R classification indicates that this capacitor is of the X7R type, which is a common temperature coefficient for ceramic capacitors. It comes in a 1812 package size or metric equivalent 4532.