Discovery 640/645: How to Replace the Ear Tips
How do I replace the ear tip on my Discovery 640/645
To Remove the Ear Tip:
Line up the elongated side of the ear tip so that it is parallel with the headset, and pull it straight out.
To Install the Ear Tip:
Hold the ear tip with the elongated edge pointing down, and push the ear tip post into the hole on the headset.
Twist the ear tip to the side and put the headset on with the elongated side of the ear tip pointing up and forward.