Aprilaire 500 Humidifier， 24V Whole House Humidifier w/ Auto Digital Control Bypass Damper .5 Gallons/ hour<div style="text-align: left;"><strong>[Product Information]</strong><ul><li id="replacementPartsFitmentBullet" class="aok-hidden" data-doesntfitmessage="We're not sure this item fits your " data-fitsmessage="This fits your "><span class="a-list-item"><span id="replacementPartsFitmentBulletInner"><a href="#" class="a-link-normal hsx-rpp-fitment-focus">Enter your model number</a>to make sure this fits.</span></span></li><li><span class="a-list-item"> Includes automatic digital control， outdoor sensor， water pad， 110V to 24V transformer， and biult-in bypass damper. </span></li><li><span class="a-list-item"> The Aprilaire 500A will cover up to 3000 sq ft. </span></li><li><span class="a-list-item"> This unit has a waterfeed rate of 3.0 GPH and will deliver an evaporative rate of .5 GPH </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/31EI7DB%2BicL.jpg" noproxy>