PR-1428 Class B is a low adhesive sealant. It has a service temperature range -65°F (-54°C) to 250°F (121°C), with intermittent excursions up to 250°F (135°C). The material is designed for use as an access door sealant or in the fabrication for form-in-place (FIP) gaskets. It can also be used to protect electrical wired, terminals and equipment against fuel moisture, dirt and short circuits.

PR-1428 Class B is a two-part, manganese dioxide cured, 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 removable seal to common aircraft substrates.