CM05FD121JO3 is a standard dipped silvered mica capacitor manufactured by Cornell Dubilier, designed for timing and close tolerance applications requiring stable capacitance over a wide temperature range. This capacitor features a capacitance value of 120 pF with a rated voltage of 500 Vdc and ±5% tolerance (J grade), meeting EIA RS153B dimensional specifications. The device operates reliably across a temperature range of -55°C to +125°C (O grade), with a minimum dV/dt pulse capability of 100,000 V/µs, and is available in a compact CD10 package format. These mica capacitors are widely used in precision timing circuits, RF applications, and other demanding environments where high stability and low loss are essential.