Product details:

Flex-a-lite 123: Electric Fan, Single, 12 in. They're only 2 5/8 in. deep, but the 15 in. wide x 13 1/2 in. high single fans move 1,250 cfm at 11 amps, while the 26 1/4 in. wide x 15 1/2 in. high dual fans move 2,500 cfm. The glass-reinforced nylon S-blades make all of that air move quietly and efficiently, and most fans include rigid brackets and through-core installation kits.