HQRP Foam & Felt Filter Kit for Shark Navigator Lift-Away NV355 NV356 Series Upright plus Coaster HQRP Foam and Felt Pre-Filter Replacement; These filters are located exactly below the dust cup and protect the motor from any debris going into it; Compatible with Shark Navigator Lift-Away NV355 NV356 Series Upright. Do not operate the vacuum with wet filters; 2 weeks DOA replacement warranty!