PR-1428 Class A is a low adhesion sealant.

It has a service temperature range from -65°F (-54°C) to 250°F (121°C), with intermittent excursions up to 275°F (135°C). The material is designed for use as an access door sealant or in the fabrication of form-in-place (FIP) gaskets.

PR-1428 Class A is a two-part, manganese dioxide cured, polysulfide compound. The uncured material is suitable for application by brush in thickness up to 25 mils. It cures at room temperature to form a removable seal to common aircraft substrates.