This is a net sinker.

It is from Tell el-Rataba. People fished for food using nets made of spun grass, wool and flax. They attached net sinkers to the bottom of the nets to make them sink, and wooden floats to the top edges if needed. The Egyptians caught and ate mainly Nile perch, catfish and eels. The poor ate fish as they could not afford to eat meat. For the pharaoh, priests and those living in the Afterlife, fish was considered unclean and they were not allowed to eat it. This is a net sinker. It is made from limestone. It is between about 2,700 and 2,850 years old, dating to the 23rd Dynasty (818-715 BCE) in the Third Intermediate Period.