I have a Quantum Futura - it come with a plastic bobbin - so I bought more Singer bobbins - not all plastic bobbins fit the same! It ruined my bobbin carriage and had to replace it - it had to be a bobbin made exactly for the Quantum Futura! The repair person showed me the ever so slight difference in the way the bobbin was made! So, as Barb 44 just stated, it is not true that a bobbin is a bobbin is a bobbin!!!! From experience I found out!