Abstract: The present invention relates to a device in a light fitting comprising a bulb and a cover (1a) surrounding the bulb, together with a socket (2) that can be functionally joined thereto by way of a connecting piece (1b) of the cover. The device is characterised in that a first part (7) insertable into the socket (2) is formed with at least one element (10), adapted to allow the first part (7) to be connected to the socket (2), so that it can be turned in relation to the socket (2) whilst at the same time being locked thereto in an axial direction. The first part (7), moreover, incorporates at least one catch element (11), adapted on the one hand to allow the first part (7) to be fixed to the cover and on the other to allow the fixing to be undone by means of tool specially intended for this purpose, whereupon the cover (1), can be separated from the first part (7), for example for changing bulbs.