Plywood subfloor lowering bracket kit. One joist bay is recessed 1″below the top of the floor joists to accommodate the depth of the linear drain. Ther rest of the shower pan is recessed 11/16″ which is limited by the height of the floor joists. Covers up to 15 sq.ft. for standard tub replacement. For use with 3/4″ plywood. If used with 5/8″ plywood, please combine with RAPID RECESS Shim Kit model#RRSHIMK. Used with RAPID RECESS Shower Pan-K.