This is an ideal bobbin case for sewing and embroidery. It is black and marked by a small triangle in the accessories catalog.
Specifications
Compatible with the following machines:

B700 E, B 720, B 740, B 770 QE, B 790, B 790 PLUS
B 500 E, B 535, B 540, B 570 QE, B 590
B 435, B 475 QE, B 485, B 480