About the model shown below:
For example, the L40 X D25 12mm x 8mm
the L is the length
the D is the diameter
12mm x 8mm is Inner hole diameter d1 and d2

Features:
1. The overall processing, lightweight, small size
2. Can absorb vibration, spring action to compensate radial, angular and axial deviation, zero backlash
3. Clockwise and counterclockwise rotary characteristics are identical
4. Made of hard aluminium alloy and stainless steel
5. Set Screw Clamp or fixed coupling, can keyway according to customer demand for processing.
6. Integrated design and installation are simple, commonly used in servo motors, stepper motors, encoders, screw driving, machine platform connection