Donaldson Replacement Filters for Airdog I Replaces FF100-2 & WS100Brand Donaldson Product Grade Replacement Part Outer Material Metal Item Weight 1. 76 Pounds Style Modern About this item Pack of 2 Set Donaldson (P551315 P550550) Replacement Filters for Airdog Replaces FF100 2 & WS100 Filter retainers need to be removed from the base. The retainers are only needed for Airdog filters. The P550550 is temporarily unavailable in Donaldson and will be replaced by Wix 33616 Product Description Donaldson (P551315 P550550)