The empirical focus of this paper is a conversational turn-taking phenomenon in which conjunctions produced immediately after a point of possible syntactic and pragmatic completion are treated by co-participants as points of possible completion and transition relevance. The data for this study are audio-video recordings of 5 unscripted face-to-face interactions involving native speakers of US English, yielding 28 "trail-off" conjunctions. Detailed sequential analysis of talk is combined with analysis of visible features (including gaze, posture, gesture and involvement with material objects) and technical phonetic analysis. A range of phonetic and visible features are shown to regularly co-occur in the production of "trail-off" conjunctions. These features distinguish them from other conjunctions followed by the cessation of talk. (Contains 10 figures, 1 table and 9 notes.)