Product review (1 stars): Not the best choice by far.
I am VERY disappointed in the quality of these filters. Especially when compared to the similar filter branded "Bestair". The construction is totally different. I have used both types. The Moistair fit POORLY with each one being a different size, one being OK, one being too long, and two 1/2" too short leaving a substantial air gap. The Moistair filter paper is nearer to construction paper and pleated ONLY whereas the Bestair is nearer cardboard with hundreds of weaves. The Moistair has horizontal glue strips to hold the paper in place which if the paper gets too wet allows the filter to collapse into a pile of snot. The Bestair is made with a metal support in the center which covers 100% of the filter and prevents distortion even if you try to bend it. Just buy the Bestair brand and avoid this cheap substitute. If you have not purchased a humidifier yet avoid these models. The cost of filters makes this one of the most inefficient methods of humidifying your home, and the need for filters to soak from the bottom means that as soon as the bottom is crusted the process stops. My 30 old Sears with the rotating belt outperforms this style 20 to 1, and the belt lasts for years. But I can't buy good belts any longer.