Protect surfaces from microbes for up to 30 days with Smart Shield Surface Protectant. The second step in the Smart Shield system, this water-based formula is great for bathrooms, kitchens, desks, doorknobs and more. Using antimicrobial nanotechnology, it creates a long-lasting invisible shield on surfaces. The patented Smart Shield formula makes use of spike-like, positively charged molecules that covalently bond to surfaces. These molecules attract negatively charged microbes to surfaces, where their spike-like structure punctures the cell walls of the microbes for up to 30 days