Collectible caps, also known as POGS (an acronym for 'passionfruit, orange, guava'), are a type of collectible game pieces that were popular in the 1990s. They are typically made of cardboard or plastic and feature various designs, such as cartoon characters, sports teams, and logos. The goal of the game is to collect as many different caps as possible. Players can trade and compete with each other to see who has the most unique collection.