Sealant not exceeding P/S 870 Class B. It has a service temperature of -65°F (-54°C) to 250°F (121°C). With intermittent excursions up to 275°F (135°C). This material simply acts as an effective barrier between dissimilar aluminum alloys or metals. Cured sealant will retain elastomeric after exposure to both jet fuel and aircraft gas. P/S 870 Class B is a two-part, manganese dioxide cured polysulfide compound. The uncured material is a high quality, low sag, low sag, thixotropic putty. Cures to form a flexible sealant with excellent adhesion to common aircraft surfaces.