Great general purpose discs for high temperature applications. They are excellent for arts and crafts applications that require a strong, thin disc. Just 1/16" thick, but still a sturdy disc. The D81 is deceptively strong for its size.
The D81SH discs are made with grade N42SH (SH = Super High Temperature) material. The SH material means that the magnets can be heated to 302° F without any loss of magnetic strength, unlike standard neodymium magnets that begin to lose strength at 175° F.
This size is also available in grade N42 as part number D81
and in grade N52 as part number D81-N52