The ka amulet indicates the power of will and intention1. This is a rare one, with arms up or down, the latter being totally abnormal (a fake?). The amulet may have acted as a substitute in case of mummy’s destruction2. Period: from Dynasty 18 onwards2

Green glaze H 2.0, W 1.8
Dynasty 21
© 2017 University College
London LDUCE-UC #31435

Blue/green glaze damaged H 2.0, W 2.4 Napatean Dynasty 25 © 2006 Musée du Louvre/Georges Poncet #E 5653

Blue/green glaze
H 2.0, W 2.4 Late Period?
© 2008 Musée du Louvre/
Georges Poncet #E 24606

References

1Petrie W F M. Amulets, 1914, p. 11 and Fig. 10a
2Andrews C. Amulets of ancient Egypt, 1994, pp. 68-69, Fig. 74b