These are awesome, high quality, custom made aluminum spacers. They are great at making sturdy standoffs/spacings for your projects.
The OD is 10mm which makes a very stable platform.
The spacer has M5 ID to give a thicker wall to keep the screw snug and centered.
These spacers can be used in all sorts of builds. For example, We use the spacers to create a space between the stepper motor and motor mounting plate. This allows for room to mount hardware such as couplers and belt pulleys to the motor shaft.
An assortment of the most popular sizes are available.