Wadi Fidan 50a is a small Roman watchtower, or castellum, and an associated well. It was surveyed by the Jabal Hamrat Fidan Project's Wadi Fidan District (WFD) Survey in 1998 (Levy et al. 2001) and excavated by JHF in 2004. It is part of Wadi Fidan 50, the largest site surveyed in Wadi Fidan, which had been heavily damaged by bulldozing in the late 1970s. This is likely the site Glueck (1935: 20) called Rujm Hamra Ifdan, although that toponym has more recently been used to refer to Wadi Fidan 77a, an Iron Age site that Glueck called Khirbat Hamra Ifdan, to distinguish it from the primarily Early Bronze Age Khirbat Hamra Ifdan to the south.