Filter Queen air purification units are among the few Class 2 medical device certified machines, providing their customers with medical grade purification day in and day out. These machines are very high end, and as you guessed it, come with a very high end price, however the level of purification they provide is second to almost none. Some of the more popular units in the Filter Queen line are the Defender 4000 series, Defender 360 series and Defender 7500 series. The machines are crucial for people who need the cleanest air because of respiratory illnesses and are super helpful for people who suffer from seasonal allergies. Sticking with the theme of expensive high end air purification, Filter Queen genuine HEPA filters are very expensive. Thankfully for the consumer, there are a good variety of aftermarket replacement filters that cost almost half the price of the traditional OEM filters. One word of caution though as aftermarket filters don't require the same certification that the genuine Filter Queen filters require. That's why the team here at Breathe Naturally spent a great deal of time manufacturing a replacement filter that meets Filter Queens standards but costs nearly half the price. Breathe Naturally MERV 17 HEPA filters stop harmful airborne particles down to 0.03 microns small at a 99.97% efficiency level. Capture mold spores, dust, dander, pollen, bacteria, virus carriers and tons more airborne particles, leaving the air you breathe clean and healthy. Our filters are perfect for those with seasonal allergies, sensitive respiratory systems and people who just want to Breathe Naturally. Breathe Naturally carbon filters are made from Bamboo carbon and are proudly made here in the USA, supporting American companies and jobs. We take pride in our specially designed carbon filters that are made to be thicker, last longer and capture more odors and particles that ultimately leads to a longer lifespan on your HEPA filters saving you money and leading to less waste. We recommend changing HEPA filters based on use, usually every 4-6 months for normal use, and every 1-2 months per carbon filter, again with normal use. Those who put extra strain on the air in their homes, such as larger families, people with pets and people who live in larger cities may want to change their filters more often. Most modern air purifiers come with a filter change indicator light that will let you know pretty accurately when you're due for a change. When changing your filters, dispose of dirty filters in the garbage. Reset filter indicator lights, and enable child lock if needed and available. Breathe Naturally firmly stands behind their filters and trusts them in their homes and the homes of their loved ones. We offer a 30-day money-back guarantee on all purchases. Satisfaction guaranteed or your money back. Our carbon filters are proudly made in the USA. All filters ship from Minnesota, a family owned and operated company. Do not place the air purifier too close to your head, and refrain from having the air blow directly towards you. If you have any questions about Filter Queen air purifiers and replacement filters or any other questions please don't hesitate to drop us an email or give us a call. All of our contact information can be found in the About Us/Contact us section of the website.