IBM 4685-K03 - Manual (Page 32)

3. Remove the black rubber ring.
Rubber ring (Black)
Attaching
1. Insert the black rubber ring. Insert the cup with the
larger opening facing up.
2. Insert the key. Be careful not to bend the spring
attached to the key.
3. Attach the key.
Rubber ring (Black)
Key
Spring
16 IBM 4685-K03 Installation, Operation and Maintenance Guide