Wingspan c.14 mm.
This species can be confused with I. masculella, but the yellowish marking on the costa, if present on masculella is closer to the head than the opposing tornal spot. In oehlmanniella, it is closer to the wingtip. In addition, the males of oehlmanniella have simple antennae.
The larvae feed on bilberry (Vaccinium myrtillus) and cloudberry (Rubus chamaemorus), at first mining the leaves, then cutting out a portable case and dropping to the ground, where they feed on dead leaves.
The adults fly in June and July. The distribution covers much of the British Isles, where in the north it can be found at high altitudes.