What are Durst Lorepin 80 buttons?

I recently bought a Durst Mivalo and there was a bag of 16 buttons marked 'Durst Lorpin 80' in the box. The discs are about 18mm in diameter, have an adhesive back with peel-off wax paper and a small raised metal piece in the center (see picture). I have absolutely no idea what these are for and a google search gives absolutely no results. Does anyone know what these are?

These are register pins. You either use a punch to put a row of precision holes in the film or use a piece of film with a hole in it and tape it to your film. These are/were most commonly used in the printing trade for registering colour separation negatives. With a punch the center hole had the slot vertical and the adjacent holes were horizontal. they will also work in 1/4" round holes. In a pinch you can use an ordinary paper punch to make your own tabs. If you need more information, let me know.

Thanks for the quick reply Richard. I am intending to use the Mivalo to punch the small holes which match my Femoneg negative carrier on the Durst L1200 for masks. The hole distance and size with the Mivalo are perfect for the Femoneg. For this use I guess I don't need the Lorpin buttons. I suppose they could be used to custom build a registration system - i.e. for exposing - by using an ordinary hole punch? Exposing in the Femoneg carrier with the Mivalo punched holes would otherwise be my option. I was intending to use cut down 5x7" film for creating a mask from a 4x5" negative attached with some tape to a plastic leader to fit in the Femoneg holes. Is there a better way to do that?

I guess my reply may have been a bit ambiguous in some respects. If you cut pieces of film about 20mm x 30mm and punch a hole in the end, then tape these to your negative as if you were putting it in a 3 ring binder... I am not familiar with the Femoneg carrier. My Durst is a Laborator54 the earlier 4 x 5 model. If your carrier has pins the same size as the buttons, then just position the registration tabs to suit. Am I making sense??. One company that made pins and tabs was "Carlson". I googled the name but didn't make a hit which I could pass on to you.