【WATERTIGHT SEALING】WELLUCK Gray sealant silicone provides the ultimate waterproof seal seam protection against water leaks, odors, UV rays, extreme heat and pressure. 100% waterproof on indoor, outdoor and underwater surfaces. Widely applicable to most surfaces such as metal, tile, ceramic, stone, wood, glass, concrete and more. 【FORMULATED TO LAST】Our Gray caulk offers reinforced pressure resistance for RV, Indoor windows and doors, automotive repair，shower and tub caulk protection; rated to safeguard against high heat, corrosion, leaks and acids for 15 years; resist black spots, stains . 【NO CLUMPY TEXTURE】 With a clog-free thermoplastic nozzle, our Gray caulking waterproof flows with just the right viscosity- not runny nor clumpy. This window sealant caulk is 100% waterproof Silicone with no fillers.（Cut the main opening of the bottle, install the clog-free nozzle, then bevel the nozzle opening, push and squeeze out the silicone sealant from the tail and it can be used.） 【ZERO-SHRINKING】WELLUCK windows silicone caulk features excellent adhesion and maintains long-lasting flexibility; Won't shrink or crack even when constantly exposured to extreme weather (-40°F to +104°F), including cold, heat, UV, or constant raindrops. 【Quick Setting & Curing】Caulking sealant surface dries in 30 minutes, sets up firmly and fully cures in 48 hours; NOTE: The time required for the caulk surface to dry & cure will vary depending on application environment（A dry construction environment of 75°F is most suitable).Our bathtub caulk is safe and delivers smooth, uniform sealing，no chemical smell.Please use it as soon as possible within 3 days after opening. TIP：When the product is filled, some overflowing and dry traces may be left after being squeezed. This is normal filling residue, please don't care.