A small rounded bobbin made for a weaving shuttle. It's 10.5 cm from end to end, or about 4-1/8 inches.
Prints without supports (need to turn 90 degrees), brim recommended for bed adhesion. The cap is designed to press-fit onto the end of the rod. For me it took some force to get it into place, but then holds well with not glue needed. May vary depending on your extrusion settings.
Shown with the hearts-weave wrap my wife is working on :)