Northern Tool offers the Strongway 48" Air Curtain for $189.99. Coupon code "254337" cuts the price to $169.99. Opt for in-store pickup to avoid the $27.49 shipping charge. That's $30 off list and the lowest price we could find. Commonly used for customer entrances, drive-up windows, and concession stands, it regulates air flow at thresholds and deters flying insects.