Keyswitch structure and keyboard

A keyboard, comprising:

• a plurality of keyswitch structures, each keyswitch structure comprising:
• a base, the base comprising a lower casing and an elastic dome, the elastic dome being disposed above the lower casing and having a hole;
• an upper casing, the upper casing being fixedly disposed above the base and having an opening;
• and
• a keycap, the keycap being detachably connected to the upper casing and having a keycap body and an impact post, the keycap body slidably passing through the opening, the impact post protruding from the keycap body toward the base and extending into the hole;
• wherein the plurality of upper casings of the plurality of keyswitch structures are formed as a single component, and the plurality of lower casings of the plurality of keyswitch structures are formed as a single component;
• wherein when the keycap is pressed toward the upper casing, the keycap squeezes the elastic dome, and the impact post impacts the base to generate a sound.