Block Sand High Crown Fenders - Ridged block sanders make incomplete contact on high crowned fenders and body panels creating flat spots. This set of 15", 21", and 27" sanders work with your standard 2-3/4" wide Pressure Sensitive Adhesive (PSA) sheet abrasive to form the most versatile sanding tool available! 1075 tempered spring steel faceplate is embedded into the urethane foam body. Removing any or all of the three rods encased in the handle adjusts the flexibility of your sander to maintain complete surface contact on flat or curved surfaces. Made in the USA.