Device box. 2 1/2 in. Made of galvanized steel. Intermediate device boxes are widely used for switch and receptacle installation in walls made of 2 in. x 3 in. or 2 in. x 4 in. studs. Models #3104 and #1804 are recommended for thermostat installation. Wraparound bracket 2 1/2 in. and 3 5/8 in. steel studs. With integral support bracket. Bulged sides for added capacity.