The B4 2/3" to Sony E-Mount Lens Adapter Package from MTF Services Ltd includes two lens adapters, a B4 2/3" to Canon EF adapter and a Canon EF to Sony E adapter. The kit enables the use of ENG style B4 2/3" lenses on cameras with either Sony E-mount or Canon EF mount, like the Sony NEX-FS100 or the Canon C-300. The B4/EF adapter feature multi layer coated optics, and both adapters are of solid aluminum construction.