This type of smooth flat hair comb is characteristic of the Naqada I Period. These combs are usually decorated with profiles of animal figures at the top. The crest of this comb looks like a head with two vertical plumes.  The excavator, William Flinders Petrie (Prehistoric Egypt 1920 p. 29), has suggested that this design originated as one with a pair of birds on the crest, but was them modified into two horns.  At the bottom of this piece there were originally six prongs which would have been used to hold coiled hair in place.  They have unfortunately all broken off close to the handle