Lucas #5500 Seam Sealer is a premium synthetic rubber based sealant and caulk. It is intended for flashing, repairing and sealing metal roofs and trailers, built-up roofing, modified bitumen, TPO and many other single ply systems. This product is ideal for caulking termination bars, metal flashings and fasteners. This product is elastic, strong, and adheres to most common roofing materials. #5500M is a semi-self leveling brushable mastic viscosity. Lucas Seam Sealer is manufactured from 100% synthetic rubber base to a mastic or semi-mastic viscosity. It contains no asphalt of other bituminous material. Lucas #5500 is formulated to apply easily by trowel, brush or caulking gun. Lucas #5500 contains anti-oxidants and light-stabilizers for extended life and reinforcing fibers that add durability and strength.