DMD 100 is a Class "F" 3 layer insulation composite used as a coil separator, slot liner, wedge and phase insulation for both manual and automatic insertion. It also serves as a primary layer and outer wrap insulation for transformers and for hermetically sealed motors. - DMD 100 is a Class "F" 3 layer insulation composite used as a coil separator, slot liner, wedge and phase insulation for both manual and automatic insertion.