filter union

band-pass filter / bandpass filter (BPF)

dust filter / dust shield, particle filter

dust shield / dust filter, particle filter

filter housing / filter unit

filter unit / filter housing

particle filter / dust shield, dust filter

finite impulse response filter (FIR-filter)

passband filter; bandpass filter (BPF)

African Union / United Nations Hybrid operation in Darfur (UNAMID)

European Defense Community / Union (EDU)

Forces Answerable to the Western Europen Union (FAWEU)

bearing oil pipe union

union joint

hose union

inlet union

European Union’s Naval Force (EUNAVFOR)

ITU (International Telecommunication Union)

air filter

filter-separator

fuel filter

gas-particular filter unit (GPFU)

home-made face filter

individual portable filter

oil filter

RF interference filter

filter stack

military-grade filter

slave oil filter

bag filter

bath filter

centrifugal oil filter

disk filter