FSA integrated headset microspacer
Sometimes integrated headsets need one (or more) of these lil' guys to install properly on some frames. If you need them, you'll know it.
Get a few just to be safe!
These are often (but not always) used between the top cover and compression ring to prevent the top cover of your headset from contacting the head tube.
• 1 1/8"
• .25 thick
• sold individually