<p>The present invention relates to a plug-in lamp, in particular for a bike, comprising a housing (3) with at least one light source (8) arranged in said housing (3). The housing (3) has an emission window (4) for the light source (8) and is designed for complete insertion of at least a portion of the housing (3) into a tubular adapter opening. The lamp comprises one or several elements (5) allowing a mechanical connection between the housing (3) and the adapter (1). The light source (8) is thermally connected to said portion and/or to said one or several elements (5) to achieve a main discharge of heat generated by the light source (8) through the portion and/or elements (5). The proposed plug-in light source can be provided lightweight and with low cost and allows an effective cooling of the light source.</p>
