Introducing the 4" x 21" Aluminum Oxide Sanding Belt Set in 3 Popularly Used Grits by POWERTEC.This premium assortment pack of 15 was designed to provide you with a cost effective set of long lasting and high performance sanding belts in a range of grits. From 80 grit to 150 grits, this comprehensive selection of popular grit sizes allows you to sand through all the stages of your project, from coarse to fine polishing. Made with open coat Aluminum Oxide (A/O) grain, they act as a multi-purpose tool best used for wood sanding, shaping, stripping and giving a smooth finish to many of your woodworking applications. Additionally, these belts work exceptionally well with lite and non-ferrous metals, blending welds, fiberglass, plastic, and rubber. Each belt flaunts an X-weight clothed backing, and possesses a strong resin on resin bond with well crafted seams for long lasting results. Whether you’re a professional or DIY kind of guy, these heavy duty sanding belts are compatible with many of your go-to 4x 21 belt sander models!Specifications:AbrasiveBelt Size: 4-Inch x 21-InchMaterial: Premium Open Coat Aluminum Oxide (A/O)GrainBacking: Strong "X" Weight Cloth BackingJoint: Strong Butt Joint ConstructionPackage: 15 pieces Sanding Belt Set Includes the Following Grit Sizes: 80 Grit; 120; Grit150Grit Selection Guide:40 - 60 Grit: Heavy Sanding and Stripping80 - 180 Grit: Removing Tiny Imperfections