Alliance Gator 006684 Nitro Silver Joint Sand 40 lbs - Gator Nitro Joint Sand is the ideal air cure, permeable jointing material. It is a ready-to-use mixture of calibrated sand and proprietary resin formula which cures when exposed to air, hardening from top to bottom of the joint. The product can be installed in wet or dry weather. It is ideal for residential and commercial pedestrian applications, porcelain tile within the Gator tile system, natural stone, wetcast stone and concrete pavers.