The Siafast system is the modern, quick-change disc system. Discs have a Velcro® like (hook and loop) fastening system. With the Conversion Disc mounted on your edger disc pad, discs press into place and peel to remove in just seconds. Easy to use, no more edger wrenches. Change your disc in 5 seconds. Cooler sanding means less clogging, discs last longer. High-quality abrasive for durability and performance. Guaranteed not to slip up to 8,900 RPM (most edgers run at 3,600 RPM). Fits all 7" edgers.