Amazon offers the Holmes Dual Blade Twin Window Fan for $16.64. Check out via Subscribe & Save to bag free shipping. That's $3 under our mention from three days ago and the lowest price we've seen. (It's the best deal we could find today by $3.) It features twin 6" blades, adjustable extender screen, extender panel, replaceable 5-amp fuse, and two speed settings.

Note: Be sure to cancel Subscribe & Save after your item ships to avoid being billed for future shipments.