#22 Smartide 2 Pack Kit for Shark Navigator Lift-Away Nv350 Nv351, Nv352, Nv355, Nv356, Nv357 Pre-Filter Foam and Felt + 1 Hepa Filter for Shark Part # Xff350 & # Xhf350 4.8 out of 5 stars 4,662 1 offer from $14.90 source https://www.amazon.com/Smartide-Navigator-Lift-Away-Pre-Filter-Filter/dp/B01AFZAQEY/ref=zg_bs_510106_22/132-0430312-5431656?_encoding=UTF8&psc=1&refRID=EKR5D7RYNHYTXJMP9XC4
