Velour backed aluminium oxide abrasive paper. The yellow coloured SIA abrasive is suitable for woods, paints, fillers and metals. This material has a velours backing, so you can make up your own discs, pads or sheets to suit any size velcro faced sanding blocks, as well as it being a cheaper alternative to buying pre-cut sheets for 1/2 or 1/3rd sheet sanders with a velcro backing pad. It is best cut from velours side with a knife, or with a pair of scissors.