The Heb-Sed (or Sed festival) was in the nature of a jubilee celebrated by the pharaoh after thirty years of rule and repeated every three years thereafter

Blue glazed Heb-Sed motif H 1.8, found in Tell
el-Amarna. Presumably issued for Amenhotep III or
during his co-reign with Amenhotep IV (Akhenaten)
© 2017 University College London #LDUCE-UC1113

Blue glaze top suspension loops broken, New Kingdom, Amenhotep III named on the right
H 3.0, W 2.0, T 0.3
Museo Egizio #6736

References

1None, Unpublished amulet