Student stein by Reinhold Merkelbach #1741, dated 1908. The Wappen represents the "Corps Hansea" founded on 11/07/1849. The colours of white-red-white are derived from the Hanseatic flags and its Latin motto "Recte facienti nihil timendum!" translates as "Der Rechtschaffene hat nichts zu furchten!" or "The honest have nothing to fear!" The coat of arms contains the motto "Ehre und Recht" meaning "Honour & Justice". The members of the "Corps Hansea", which still exists today, are called "Bonner Hanseaten" or more commonly "Bonner Hansen" or even just "Hansen".
References: Corps Hansea  Wikipedia