Hart & Cooley® Floor Register, 2-Way, Series: 421, 4 x 10 in, 9-5/8 in Duct Width, 3-3/4 in Duct Height, 5-1/2 in Overall Length, 11-1/2 in Overall Width, 27 sq-in Effective Area, 1/2 in Blade Spacing, Steel, Golden Sand Enamel, Domestic