HowPlumb Dual Blade 9-Inch Twin Window Fan with Cover Portable, White Quiet operation, 2 speed dial control, ETL/US Listed Auto-locking accordion expanders adjust to fit most windows from 22 1/2" to 33" Manually reversible by rotating the fan for intake (brings fresh air in) or exhaust (takes stale air out) Removable feet for tabletop use and built in handle. Removable fabric cover keeps out hot air, humidity, and bugs when not in use Measures 22 1/2" - 33" L x 4" W x 10 3/4" H