Magnets make building and maintaining your planning board easier. Use different colors to categorize a group. Arrange data easily and quickly when changes become necessary. Super-strong magnets hold up to 10 sheets of letter-size paper at once. Each magnet is made of a magnet stone encased in plastic.Magnets make building and maintaining your planning board easier. Use different colors to categorize a group. Arrange data easily and quickly when changes become necessary. Super-strong magnets hold up to 10 sheets of letter-size paper at once. Each magnet is made of a magnet stone encased in plastic.