These are 2 BOBBIN CASE+10 BOBBIN for SINGER 31-15 331K, 431D CONSEW 30

Also will fit many following models of industrial sewing machines :

for Adler : 37

for Alfa : 157

for Consew : 30

for Necchi : 500, 510, 512, 513, 514, 515, 520, 522, 523, 524, 525, 527, 529, 532, 534, 539, 554, 600, 601, 602, 603

for Singer : 31 class (except 31-19, 31-20), 31-15, 44-10, 44-12, 331K, 431D