This is a set of five round vintage silvertone metal button covers which have been in storage since the 1990s. Each is comprised of one acrylic iridescent center rhinestone surrounded by smaller acrylic clear rhinestones. 

All five are in good vintage condition, showing only normal signs of wear such as some discoloration (patina?) along the edge of some and the metal of the some of the back connector pieces. They are all approximately 0.75".