The Infila Automatic Needle Threader was invented in Italy in 1952 and still going STRONG! because it is so simple to use. 
There are two ‘funnels’ (one for an small needles and one for a larger ones) in which you place the needle, eye down.
You lay the thread in a gulley next to the funnel and slide the button which pushes the thread through the eye of the needle. If you want to thread multiple threads, you can do this one at a time, or all together. 
It really is that simple.
Comes with instuction leaflet.