Thicker when wet and more rigid compared to original Honeywell or Vicks filter. Won't fall apart Fits HCM350b, series, HCM315t series, HCM710, and Quietcare Quiet Care UV Light Tower Humidifer Our best rated filters replace HAC-504, HAC-504aw, HAC504aw, HAC-504v1 Honeywell humidifiers filters The evaporative wick is treated with a germfree antimicrobial agent to help prevent mold in home Lifetime Warranty and 100% Money Back Guarantee if you are unsatisfied. No risk purchase