My 301 was advertised as a heavy duty machine, which it is not, but it is capable of any household sewing. It doesn't need to be babied because it is light. The gears and inner working are all full size and good steel. Only the housing is aluminum. Mine came with four layers of leather under the presser foot with rows of stitching.. My daughter was fascinated and played with it. I had her stop. It is not an industrial machine. If I want to sew four layers of leather - and I have, I'll use the Elna or Necchi. The Elna loves that kind of sewing. I haven't tried with the Necchi.