Product review (5 stars): You NEED These
<a data-hook="product-link-linked" class="a-link-normal" href="/Honeywell-HMP-12P-QuickSteam-Mineral-Absorption-Pad-12-Pack/dp/B000BV6D5O/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">Honeywell HMP-12P QuickSteam Mineral Absorption Pad, 12 Pack</a>
Great Product! If you do not have a home water softener, or the desire to buy distilled water at 2 gallons per day, you NEED these Mineral Absorption pads. I've run my unit 24/7 with the exception of cleaning and refilling - all winter. With the pads, the cleaning is easy, very little mineral deposit inside the base. With an old pad or without one at all, what a mess - thick crusty hard water deposits built up everywhere inside the base!

However, I do think somewhere in the information about this product it should be said that these are the 3 1/4" pads.