File:KOMA Elektronik FT 201 Analog State Variable Filter & 10 Step Sequencer - patchbay interconector (by Audiotecna).jpg - Wikimedia Commons
Electronic filter - Wikipedia
WE-SL Series Filters - Würth Elektronik | DigiKey
810913020 Wurth Elektronik | Wurth Elektronik, WE-CLFS 20A 250 V 50/60Hz, Chassis Mount Power Line Filter, Fast-On, Single Phase | 185-7134 | RS Components
EMCoS
WE-CNSW SMT Common Mode Line Filter | Passive Components | Würth Elektronik Product Catalog