The problem is that there are only 49 items for this layer so this achievement is unobtainable..

Please add one more item or change the request to 49 items.

...I'm sure that, at some point, another item will be made for the finger layer.

I know but the thing is that there are a few users that have this achievement, the users got it before the update that moved a few items to another layers.. I hope a new items for this layer will come out soon :)