- Features : • 100% Pure Silicone. • For Interior / Exterior applications. • Can be use as sealant or adhesive. • Waterproof, ideal for structural materials on indoor or outdoor applications. • Mildew & weather resistant. • Flexible from -50°C to 230°C temperatures. • 40 year life. ProLine POWERSEAL™ General Purpose 100% Silicone Sealant is a superior quality product permanently flexible, designed for joining and sealing structural materials on indoor or outdoor applications. Formulated for areas where a watertight, mildew resistant seal is needed.