This is a custom press-fit keycap designed for standard 6×6 mm tactile push buttons, like the ones commonly included in Arduino starter kits such as the Arduino UNO R3 kit.

The push button used for this design has:

• Body size: 6 mm × 6 mm
• Actuator (button top) diameter: ~3.37 mm
• Actuator height above body: ~1.65 mm

This keycap is specifically designed to fit only on the round actuator, avoiding any contact with the switch body or breadboard. This ensures smooth button travel and prevents interference with surrounding components.

The internal socket includes a shallow depth and slight chamfer for easy installation while maintaining a secure friction fit. Once installed, the keycap stays firmly in place during normal use but can still be removed when needed. No glue or additional hardware is required.

This design improves usability by providing a larger, more comfortable pressing surface while also giving your project a cleaner and more finished look.