Metacaulk® 1200 is a single component, highly elastomeric water based firestop mastic for general construction gaps and voids. Metacaulk 1200 caulk grade is a non-sag sealant that is easy to apply from a caulk gun or troweled. It cures to an elastomeric membrane seal that is suitable where dynamic movement is expected. Can be applied to horizontal and vertical surfaces for interior and covered exterior application that cures to a paintable elastomeric membrane seal. Application temperature 40°F to 120°F.
Tested to ASTM E 1966 (UL2079, CAN/ULC S115, ASTM E 814 (UL 1479) & ASTM E1399
 
Features 
Extremely flexible cure
Excellent dynamic movement characteristics
Excellent Freeze-thaw
STC rating 65
UL Classified up to 4 hrs
Tested to ASTM G21 standard
3 year shelf life