The set includes all ten manned Gemini missions, the Gemini Program Emblem and the NASA Vector Emblem, a total of twelve pins.

These pins are made by AB Emblems the NASA Contractor for Mission Emblems

Each pin is approximately 1 inch in diameter.

Look for the embossing on the back of each pin which reads:

Apollo [mission number]
NASA
ABEmblem.com

to make sure you are getting the authentic AB Emblems pins.