Some time ago, I suddenly was certain I needed a trigger winder on my 1938 Leica IIIa. Not having a transport lever on the camera made it a bit slow in use when I am shooting in the streets.
The Leica-made trigger winder is in fact a trigger bottom plate. It takes the place of the normal bottom plate, it has a spring to make the trigger return and that construction has one flaw: the trigger is connected to the film winder axle with the spring by means of a silk ribbon. And these ribbons sooner or later always snap.