credit card.‡
This is one tube of StopGap Acoustical Sealant by Auralex, which is a highly elastic, water-based sealant used for reducing sound transmission at the perimeter of wall systems, or around electrical box cutouts, to achieve specified STC/MTC values. The surface dries to a tough film but the sealant remains flexible and stays pliable for up to five times longer than alternative brands.
StopGap Acoustical Sealant has no residual run-off, can be painted, is non-staining, and meets ASTM C-834 standards for flame retardancy. The sealant comes in a large 29oz caulking tube and therefore requires a larger than normal-sized caulking gun, which can be purchased at any local hardware store. Coverage per cartridge is approximately forty linear feet with a 3/8" bead applied.