Sea Otter Enamel Pin! Hard enamel pins are similar to soft enamel, however instead of sitting below the metal line, enamel is layered up, then polished back down to the same level. This gives the hard enamel pin a much more polished appearance and is smooth to the touch. - This pin measures approximately 30mm between the furthest points. - The pins come on a nice card backer and has a rubber clasp.