A final component is an optional epoxy primer.  Primers for heat-shrinkable sleeves work in the same manner as an FBE primer does when it is specified on 3-layer polyolefin pipeline coatings and is typically applied between 150 μm and 300 μm thick. Usually, the primer of heat shrinkable sleeve is two components non-solvent Epoxy, one is primer base and the other is curing agent.