Wingspan 8 to10 mm. The adults resemble several other Coleophora species, and are most reliably identified by dissection of the genitalia.

Near to areas with Juncus rush species.

It flies mid May to June at dusk and night.

At the larval stage it can be distinguished from other Juncus feeders by its grey case heavily encrusted with blackish frass and debris, with paler longitudinal expansion grooves.

It is widespread and locally common in England, but less so in Wales and Scotland. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as common.

It appears to be uncommon in Leicestershire and Rutland, where there are few records. L&R Moth Group status = D (rare or rarely recorded).