Think Crucial Replacement Shark NV400 2 Foam & 2 Felt Filters Fit NV400, Compatible Part # XFF400 HIGH QUALITY FELT & FOAM FILTERS replaces your existing Shark filters. Get back to having a clean air to breathe again! Fits Shark NV400 Upright Vacuums. HEALTHIER LIFESTYLE! No one wants breathe dirty air in their home and if you don't clean your air filter that will be exactly what you'll be doing! Replacing your filter will help clean your air purifier's air and allow for a healthier lifestyle! This filter helps keep our household dust, fine powders, and drywall and cement dust. EASY TO INSTALL so you can get back to cleaning as soon as possible! Simply remove your old filter and put this brand new one in it's place! This filter is also washable and reusable. Compare to Shark Part No. XFF400. SAVE MONEY by using a new air filter! When your vacuum has a clogged or dirty air filter it can cause it to work harder which will end up hurting your electric bill! GUARANTEED SATISFACTION because of a 30 day full money back guarantee and a trusted Think Crucial warranty. We are so confident in our products that we have no problem giving you every penny back if you're unhappy with your purchase. You won't see promises like that from big box brands!