Shark NV42 Foam & Felt Vacuum Filter Kit. Designed by FilterBuy to Replace Shark Part # XFF36. Kit includes all 3 foam / felt filters used on Shark NV42 Vacuum. Designed to replace Shark Part # XFF36. Kit includes 2 washable pre foam filters and 1 post motor filter. Premium Allergen Filter Designed by FilterBuy to fit Shark Navigator Upright models UV402 and NV42. FilterBuy: Breathe Better!