Hey all you Viking owners the pink bobbin winder works with the green bobbins. You have to put the bobbin on upside down for the thread to wind in the correct direction but it works great. It is a snug fit so you get a good fill. I too didn't see the purpose of one until my winder on my machine broke and after spending over a hundred dollars to get it fixed it didn't tension wind properly. Pink winder to the rescue and now I love it.