Polyurethane sealant has many advantages when compared to other commonly used sealants.
•  Does not shrink or crack—it does not have an evaporation cure like most other sealants.
•  Does not conduct electricity—water based sealants can facilitate shorts to ground.
•  Has a low viscosity (flows easily) is easier on your hand, and is self leveling.
•  Can be cleaned up with rubbing alcohol.