This material is designed for fillet sealing of fuel tanks and other aircraft fuselage sealing applications. The cures sealant maintains excellent elastomeric properties after prolonged exposure to both jet fuel and aviation gas. PR-1440 Class B is a two-part, manganese dioxide cured polysulfide compounds. The uncured material is a low sag, thixotropic paste suitable for application by extrusion gun or spatula. It cures at room temperature to form a resilient sealant having excellent adhesion to common aircraft substrates.