I don't have one but I read several places it does not work with Husqvarna Viking green bobbins

I don't know Carolyn, I've just had a look on the internet at one and there seems to be 4 spindles. Just go to YouTube type in the heading below and watch the video, only goes for a couple of minutes. Love Cris

How to use Simplicity's Sidewinder Portable Bobbin Winder

I have one and it do not work. You will need to put fill the bobbins upside down and is hard. I use it for my old machines.

I have the sidewinder and use it on the Pfaff/Viking green bobbins. There are 4 different spindles - you just have to make sure you get the right one. I've used it for my Janome Gem and my Pfaff Creative Vision 5.5 (which uses the green bobbins) without any problems.
Vida

I have one. My DH bought it for me a few tears ago. It sits on the shelf though. I very seldom use it. I think my sewing machines do a better job winding the bobbins.

I have one and when I had my Husqvarna it did not work on those. I use it for my Janome. Does not seem to work with the Bernina bobbins either. Hugs, Mary

Hi Carolyn< I bought a second hand one at the end of last year. What a wonderful tool to speed up winding while the embroidery machines are running. No problem with the Elna (also known as a Janome) As someone said there are different spindle sizes and I get more bobbin fill on the spools. Success story for me! Tx from South Africa