The Skuttle A04-1725-010 is the correct replacement wick filter media for the following humidifier models:
The Skuttle Humidifier Wick Filter Media Replacement is a replacement wick filter for the Skuttle Model 35, 38, and 39 whole house humidifiers. This Skuttle evaporator pad measures approximately 10 3/4" x 10 1/2" x 1 3/4" and utilizes honeycomb filtration to trap mineral pollutants found in water. This Skuttle filter pad will help prevent these pollutants and larger particles from entering your home. Skuttle humidifier filters should be replaced every 6 to 12 months depending on your climate or if you live in a hard water area.
Skuttle Humidifier Wick Filter Media Replacement specifications: