An identification device adapted for attachment to an insulated electrical conductor includes a pair of generally-rectangular marking plates having planar first longitudinal horizontal surfaces. A plurality of laterally-spaced resilient tension members connect together corresponding side portions of the marking plates, thereby to bias the marking plates toward a normally closed condition in which the marking plate first surfaces are in contiguous engagement. The marking plates are separable against the biasing force of the tension members toward an open condition for receiving longitudinally between the plates and the tension members the free end of a conductor. Upon release, the marking plates are displaced toward a clamping condition in parallel spaced longitudinally-arranged contiguous engagement with diametrically opposed circumferential surfaces of the conductor. The marking plates are pivoted to the open condition about a pivot axis defined by chamfered end surfaces of the plates.