JTCAN INDUSTRIES Premium tools designed and manufactured by auto body guys for auto body guys, right here in the USA! Unique benefits of High Productivity Set of 9 VELCRO Vacuum Sanding Blocks New technology allows you to sand double curved and multi curved surfaces quickly and accurately.Blocks are ideal for sanding newer vehicle shapes. Blocks reduce wrist rolling, drastically lowering worker fatigue!Unique dynamic action is superior to static flat-bottomed blocks.Sanding straight down a double curved panel is now possible, resulting in laser straight results in a fraction of the time!Blocks make greater contact with curved surfaces for fast turnaround!Helps you use less auto body filler, saving you money! Blocks in this listing designed for VELCRO Vacuum sandpaper.Blocks that utilize adhesive sandpaper or VELCRO Vacuum sandpaper also available. (See other listings)You get 3 (12″) blocks, 3 (6)” blocks and 3 (3″) blocks in 3 variations.3 variations are:High Productivity Round for concave areasHigh Productivity Flat Flex Edge for areas of transitionHigh Productivity Curve Huggr for double curved areas.Body work is our passion! These blocks were created to make your life easier! We have a unique variety of block types and sizes available, check out our other listings.