The part number for this component is 1210Y1K00392MER. It is a CAP CER 3900PF 1KV X7R 1210, which refers to a specific type of ceramic capacitor with the following characteristics: capacitance value of 3900 picofarads (pF), ±20% tolerance, and voltage rating of 1000V (1kV). The component is in a 1210 package size, also known as metric size 3225.