Our colorful die-cast Enamel Pins feature historical figures, cultural icons, and big ideas. They’re packaged in sets of two with rubber pin backs that really hold on. Set of two pins with strong black rubber backing. Made of brass and zinc alloy with black nickel plating, and hard enamel coloring. Now your backpack or favorite jacket can join the cultural conversation! Click on The Unemployed Philosophers Guild near the product title to see more smart and clever gifts. UPG truly has presents of mind.