Simplifies stair construction and eliminate the need to calculate and notch stair stringers. Stronger and safer than wood blocking, and the angle and fasteners are hidden from view. Use the SCA9 for single 2x10 stair treads and SCA10 for double 2 x 6 stair treads. Requires 1/4 in x 1-1/2 in lag bolts. Meets ICC-ES ESR-1280, FL11664 and L.A. City RR25749 codes. For additional information on installation, Please See USP Lumber Connectors charts in the Orgill paper catalog R7 Reference Pages.