No real difference except another here said the HM-36 has a cap across the mic element. He removed it and they sounded the same. They can be used interchangeably. Gary K8IZ >Is there any significant difference between the ICOM HM-12 and HM-36 hand >microphones, or can they be used interchangeably? (Say, on a 756 PRO) > >73, Blair k3yd Gary Fiber K8IZ GROL PG-19-6691 Washington State Resident