Use ubiquitous screw-mount M42 lenses with your FujiFilm X-mount body. Many legacy optics including Praktica, 1960's Pentax as well as many other Japanese, European and Soviet-era lenses will fit this adapter.
From the manufacturer:
This adapter allows you to use M42 42mm mount lenses to fit on Sony NEX E-Mount mirrorless Digital Camera. Smooth surface for effortless mount, Infinity focus allowed. Compatible Cameras (Including, but not limited to): Sony NEX-3 NEX-3C NEX-3N NEX-5 NEX-5C NEX-5N NEX-5R NEX5T NEX6 NEX7 NEX-F3 a6000 a5000 a3500 a3000 Alpha A7 A7R NEX-VG10 VG20 etc NOTE: This adapter will NOT fit on the Sony a7S, a7 II, a7S II, and a7R II. Quality: Copper; Brand Name: K&F Concept Smooth surface for effortless mount, fine made to be lightweight and strong.