Replacement Whirlpool 8171434k Large Air Purifier Carbon Pre-filters, 4-pack. Replacement for Whirlpool 8171434k Large Air Purifier Carbon Pre-filters, 4-pack Helps remove household odors including: smoke, cooking and pet odors Carbon activated filters are used to collect large particles such as dust, pet dander, or pet hair so your hepa filter will last longer Fits Whirlpool air purifier models AP300, AP350, AP450 and AP510 BulkFilter Brand