Abstract: A lockable cover and seal for a threaded nozzle or spout, such as a hose bib cock assembly having a passageway, an end face, an external threaded portion adjacent the end face, and anti-siphon valve in the passageway including a portion protruding outward of the end face, generally includes, in combination, a lid, a seal, a swivel arm, and a shielding cap. The lid is bell-shaped and has a central axis, an inner end including a threaded portion for threaded engagement with the threaded portion of the spout, a central cavity and an annular shoulder facing inwardly for juxtaposition to the spout end face. The seal includes an inner side for sealing against the end face of the spout and an outer side for sealing against said annular shoulder and a forward extending central recess for receiving any protruding portion of the anti-siphon valve.