Loctite 554 provides maximum solvent resistance on threaded fittings and pipe up to 50 mm (2 Inch) in diameter. It is recommended for refrigeration systems and service with strong chemicals. - The sealant is used in place of specialty non-hardening compounds, litharge, glycerine and sealing tape. This product is not for slip fitted tube joints. This product is typically used in applications up to 149 °C.