This is a 0603-sized ceramic capacitor with the designation CER 18PF 200V C0G/NP0. It has a capacitance value of 18 pF and can withstand voltages up to 200V. The C0G and NP0 designations indicate that it is a type of Ceramic Capacitor, also known as an NPO (Negative-Positive-Omega) capacitor.