PR-2050 Class B is a rapid curing compound designed for aerodynamic smoothing and gap filling applications. It has a service temperature range of -65°F (-54°C) to 250°F (121°C), with intermittent exposure up to 400°F (204°C). This product has a low shrinkage and cures to sandable hardness in at least one hour at 77°F (25°C) or above. When cured, PR-2050 Class B remains flexible, reducing potential cracking problems that can be experienced with more brittle sealing compounds. PR-2050 Class B is a two-part, epoxy cured. Permapol® P-3.1 polythioether compound. The cured product will not degrade after limited exposure to jet fuel and aviation gas, nor with limited contact to diphosphate ester based hydraulic fluids. PR-2050 Class B exhibits excellent adhesion to a wide variety of properly prepared aircraft surfaces.