OSI SC-175 Draft & Acoustical Sound Sealant - Case of 12 Its primary function is to achieve and maintain the specific STC (Sound Transmission Class) value of the system designed. This sealant can be used in office buildings, hotels, apartment complexes and other types of commercial and residential construction. OSI GreenSeries Draft & Acoustical Sound Sealant exceeds LEED green building requirements, is low V.O.C., and is low odor. It can be easily cleaned while still wet with soap and water. Coverage: 85 linear feet of 1/4" bead, 40 linear feet of 3/8" bead.