Here's The description :

Circular Shape: The oscillator is housed within a circular casing, possibly made of metal or plastic, with a diameter suitable for the intended application. The circular design may be chosen for specific space constraints or aesthetic reasons.

Crystal Element: Inside the casing, there's a small piezoelectric crystal element responsible for generating the 20 MHz signal. This crystal is typically made from quartz or another piezoelectric material known for its stability and frequency precision.

Frequency Stability: The oscillator is designed to provide a stable output frequency of 20 MHz over a wide range of operating conditions, including temperature variations and electrical noise.

Mounting: The circular casing likely features mounting holes or tabs for easy installation onto a circuit board or other mounting surface. The design ensures mechanical stability and secure attachment.

Electrical Connections: The oscillator will have electrical connections, usually in the form of pins or solder pads, for connecting it to the rest of the electronic circuitry. These connections may be arranged around the circumference of the circular casing.