PR-1775 Class B is a non-chromate, corrosion inhibitive sealant with a 2 hour application life. It has a service temperature range from -67F (-55C) to 248F (120C), with intermittent excursions up to 300F (149C). This material acts as an effective barrier against the common causes of corrosion on aluminum alloys or between dissimilar metals. The cured sealant maintains excellent elastomeric properties after exposure to both jet fuel and aviation gas.PR-1775 Class B is a two-part, manganese dioxide cured, Permapol P-5 polysulfide compound. 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.NSN: 8030-01-370-2161.