OUTSIDE dimensions as follows:

Brass register, square, 29.25 x 20.25 inches (qty 1) $375

Brass register, square, 26.25 x 18.25 inches (qty 2). $350

Brass vent, square, 23.25 x 17.25 inches (qty 1) $300

WHAT IS THE DIFFERENCE BETWEEN AN AIR VENT COVER AND A REGISTER? An air register has the capability of adjusting the air flow by opening and closing a damper or flaps, usually found at the bottom of the air register. An air vent cover, simply covers the duct without the added feature of adjusting air flow