A quick and dirty little clone of a Leica VOOLA 16621 adapter. It goes inside an a36 hood or filter and then the little fingers go on either side of the aperture control tab on the 50mm Elmar f3.5. With it installed you can loosen the filter or hood and use them to change the aperture on the Elmar without needing to remove them. Probably works on any decent Elmar clone too, but I can't promise it. This works in both a36 hood and filters and with my Elmar.