Abstract: The dashboard of the automobile has an opening through which a tubular casing projects behind the dashboard. On the casing is a bell having a tubular extension telescoped on the casing. The bell, its extension and the casing are clamped to the dashboard. A trigger is pivoted to the tubular extension and has a hammer to strike the bell, a trigger finger projecting into the casing, and a spring to bias the hammer against the bell. Slidably and removably mounted in said casing is a push-pull unit comprising a plug telescoped within a sleeve and adopted to be moved forwardly relative to the sleeve to compress a coil compression spring between the plug and sleeve.