HIGH TECH FABRIC GUARD Powerful enough to protect fabrics in the harshest environment ...outdoors. Yet 303 High Tech Fabric Guard is safe for the finest fabrics, wool, silk, and fine leathers û including suede. 303 High Tech Fabric Guard restores lost water repellency and stain repellency to factory new levels, resists soiling, impedes mildew formation and helps protect against the sunÆs harmful UV rays.