Abstract: Disclosed is a shroud configured to convert an open emitter reflex sight into an enclosed emitter reflex sight. More specifically, the shroud includes a transparent window and is configured to be attached to the main body of the housing and thereby form an enclosure for the emitter of the reflex sight. In some implementations, the shroud is used in conjunction with a drainage plug assembly configured to seal drain openings in the main body of the open emitter reflex sight.