Excellent sanding performance for professional use. Hard wearing paper and Velcro back provide smoother finish and longer paper life.Application: Sanding wood, Regular steel and painted wood. Decorating.Features: Extra hard wearing aluminium oxide and velcro backed paper . Pack of 10.Hole: 3+3Compatible with: BO4554 BO4561 : HitachiMaterial: Wood, Regular steel and painted wood.How Do I Know What Grit of Sandpaper I Need The grit you use depends on what job you are trying to do.The lower the grit the rougher the sandpaper and conversely, the higher the grit number the smoother the sandpaper. The table below gives you an idea of what grade you may need for your application. Grade of GritCommon NameUses40-60CoarseHeavy sanding and stripping, roughing up the surface.80-120MediumSmoothing of the surface, removing smaller imperfections and marks.150-180FineFinal sanding pass before finishing the wood220-240Very FineSanding between coats of stain or sealer.280-320Extra FineRemoving dust spots or marks between finish coats360-600Super FineFine sanding of the finish to remove some luster or surface blemishes and scratches.