Methacrylate ester acrylic thread sealant which provides maximum solvent resistance on threaded fittings and pipes up to 2 in (50 mm) in diameter.LOCTITE 554 is a red, methacrylate ester acrylic thread sealant liquid which provides maximum solvent resistance on threaded fittings and pipes up to 2 in (50 mm) in diameter. The sealant is used in place of specialty non-hardening compounds, litharge, glycerin and sealing tape. It is suited to temperatures up to +300.2 °F (+149 °C).