401 A for me also. I have had mine for 57 years and it has never let me down no matter how thick or thin the fabric I put through it. It is still my right hand for all my sewing. I have a newer Brother about five years old I bought as a backup and for more stitches and I like it but when I set down to start a new project I go to my old friend that has never let me down.I have had several people who have tried to buy it from me but I will never let it go.