Rectorseal 66334 Metacaulk Mortar, 45 .lbsRectorseal 66334 Metacaulk Fire Rated Mortar is a rapid hardening gypsum cement compound with the best combination of workability, strength fire resistance. When mixed with clean water to a suitable consistency it forms a rigid, gas tight, fire resistant seal. Features Systems rated for up to 4 hours tested in accordance with ASTM E 814 (UL 1479) and ULC S115 95 test standards. Non sag adjustable consistency (pourable or trowelable) Sets without