Original mouthpiece for candlestick or wood wall phones. Has 15/16" thread for Kellogg mounts. Also features the "K" marking in the centre. The Kellogg Mouthpiece should also fit on phones for the following types of manufacturers: North, Dean, Modern, Manhattan, Couch, Ericsson (Coarse), Utica Fire Alarm, Voight Berger, Sumter, and Swedish American