After the carb is off, the details of the model and number of the carb. On one side is the embossing of the model, C1Q. This is a family of Zama carbs used on many Stihl trimmers. The model number is etched on the opposite side. It may be very difficult to see. This number is usually not visible when the carb is mounted on the engine, but it easy to spot when the carb is removed. In this case, the number is S110A.
Beware of this model number. One mechanic told me that FS90R machines have four different carbs. A chart I found on Internet showed the number to be S131. Clearly, that is wrong for my machine. An S131 uses a different repair kit, hence the importance of having the right number.
The repair kit comes in a plastic bag. It includes the gaskets and diaphragms necessary to replace all of them, plus some internal parts. I chose not to replace the internal parts. The full repair kit is an RM-97, the 97 unique for this carb. There are many different RM kits.
As a side note, other kits of just gaskets and diaphragms is available. These kits are a GND-xx number. I believe the xx is 55 for this particular model. This G & D kit would have been an alternative choice, but I ordered a full kit, a couple of dollars more. The RM kit was about $10.00. I did not use the metal parts for internal components in this repair.
You can see the items included in the kit. The diaphragms are very fragile and need to be handled with care.