PCO# PO4-0022 calls for the use of CiDRA Corporation Part Number 52307-01 Sealant, Pipe & Thread, PTFE Paste on the Teflon seal on fiberglass covers. The sealant acts as a lubricant during initial installation of the cover, and also acts as a secondary seal against moisture entering the cover. The upper and lower cover seals are lightly coated with the sealant just before installation of the process pipe.