Product review (5 stars): Perfect fit, easy once a year replacement
Love that this filter only needs to be replaced once per year.  This system does a great job adding humidity to our house in the winter.  We live in a very dry climate so its a lifesave!  It was a perfect fit for our&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/Aprilaire-600M-Whole-House-Humidifier-with-Manual-Control/dp/B000PY1IQ6/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">Aprilaire 600M Whole-House Humidifier with Manual Control</a>