The CAP CER 2.1PF 25V NP0 0805 is a type of ceramic capacitor with a capacitance value of 2.1 pF and a tolerance of ±0.5pF. It operates at a voltage rating of 25 volts and has the C0G or NP0 dielectric material, typically used in applications requiring stable and low-loss capacitance values. The part number also specifies that it is packaged in the 0805 metric package size (2012 inches).