B-Line Box Mounting Bracket, Telescoping, 1-1/2 in, 2-1/8 in D Box, 11 to 18 in Stud Spacing, For Use With: 1-1/2 in, 2-1/8 in, 2-1/2 in and 2-13/16 in Deep Box, Pre-Galvanized Steel, Zinc Phosphate