The C connector is a medium size RF connector comparable to the N connector. However, it has a bayonet locking and has Teflon as dielectric.
Due to the fact that the dielectric is overlapping, it can be used in applications with operating voltages of 1,000 V rms. It has an impedance of 50 ohms. When subjected to heavy mechanical stress or vibration, the RF characteristics are degraded because of the bayonet locking mechanism.
The C connector has an impedance of 50 ohms, is designed for the frequency range up to 11 GHz and the voltage standing wave ratio( VSWR) is 1.35 to 11 GHz.