The whorls are slightly convex, almost flat, with shallow sutures.
The body-whorl forms about 70% of the shell height; above it the spire has five whorls when fully grown: globular protoconch (1 & 2), rest of spire (3, 4 & 5) and body-whorl (6). Banded specimens usually have a single, broad, abapical (= in lower half of whorl), brown band on the whorls; hence the specific epithet unifasciata. The brown band on spire whorls is narrower than on the body whorl because subsequent whorls overlap the band. Shell height 2.9 mm. Dorset, England. April 2016.