One epididymis (pl: epididymides) is located above each testis. The epididymides receive sperm from the testes. In addition to storage, the epididymides provide a maturation zone, "quality control center" and give time and space for capacitation to begin.

The duct of the epididymis is lined with stereocilia. The name stereocilia is a misnomer. They are not cilia at all, but rather flexible, nonmotile microvilli that absorb excess fluid and pass nutrients to the sperm in the lumen of the tubule.