Tactile buttons are commonly used to create basic input interface (you wire them on pins configured as input).
Those tactile buttons makes 6mm wide. Using normal size buttons is really common in electronic project.
This kind of button has a standard tactile button size (6mm), so they take less place on a breadboard but are still confortable to use.
Those buttons are compatible with breadboard (2.5mm pitch) and prototyping plate (like the "PermaProto" prototyping plate)
The button offer a "Normally Open" (NO) contact. Which means that no current flows inside the button unless you press it down. The contact stays closed and allows the current to flow inside it when it is pressed. Then the current stops to flow when the button is released. It is a momentary button.
For each order, you will receive 10 buttons. They are quite useful so it is a good idea to keep some of them available in your toolbox.