ProWood FR Backer Block is your on-site solution for light gauge metal (LGM ) wall stud framing. Each block is pressure treated with ProWood FR code-approved fire retardant to reduce flame spread and smoke development. These precut blocks are used to support installation of interior cabinets, vanities, shelving, grab rails, trim and more. And because they’re made from ProWood FR pressure treated dimensional lumber, the holding strength is much greater than plywood.