Aprilaire 4332 Damper Assembly<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"> Aprilaire #4332 damper assembly - includes damper blade， spring and knob.  fits models 600， 500， 400 </span></li><li><span class="a-list-item"> The Aprilaire 4332 humidifier damper assembly is a damper assembly kit that includes a damper blade， spring and knob </span></li><li><span class="a-list-item"> The Aprilaire 4332 damper assembly is designed for Aprilaire models 400， 500， 550， 550a， 558 and 600 humidifiers. The Aprilaire 4332 humidifier damper assembly is a damper assembly kit that includes a damper blade， spring and knob </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/41dWDvDPi%2BL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/31KJdNDfe7L.jpg" noproxy>