3M Electrical Moisture Block (EMB) is a is a specially formulated rubber adhesive/sealant for moisture proofing wire bundles. Resistant to salt water, corrosive chemicals and automotive fluids. Flexible over a wide temperature range. Easily installed. Flame retardant.3M Electrical Moisture Block (EMB) is a self fusing, rubber based insulating adhesive/selaant designed to prevent the migration of water along harness wiring. EMB block is supplied on a release liner and offered in three standard sizes to accommodate different size wire bundles. It is compatible with typical wire insulation such as PVC, Hypalon(R) and crosslinked polyethylene.