Sikaflex NP 1 (Formerly MasterSeal NP 1) is a premium grade, moisture cured polyurethane sealant that has excellent adhesion and bonds to most construction materials without a primer. It can also be used in green concrete applications. Resists aging and weathering and is highly flexible with joint movement capability +/- 35% and has a wide temperature application range making NP 1 suitable for all climates. Designed for all types of joints where the sealant joint depth falls between the maximum depth of 1/2" and minimum depth of 1/4". Suitable for water immersion with documented performance in wet areas. It is compatible with non-rigid coatings and can be painted. Can also be used as an acoustical sealant to increase system STC value. It minimizes sound transfer and supports high STC ratings. UL Listed; Passes 4–hour, 4–inch, fire and hose stream test when used with Ultra Block or mineral wool. Sikaflex NP 1 (Formerly MasterSeal NP 1) is a one-component, high-performance, non-priming, gun-grade, elastomeric polyurethane sealant. It requires no mixing and typically requires no priming to bond to many materials, including concrete and masonry. Used as an acoustical sealant, Sikaflex NP 1 reduces sound transmission in partition systems to support high STC values by sealing spaces around cut-outs and at perimeters of partitions. The sealant cures to a tough rubber to form a long-lasting acoustical seal.