Entry Sensor Installation on Basement Window

After almost 3 1/2 years my basement window entry sensor (SS3) almost fell off. The magnet is installed on the metal  beam on top and the main body of the sensor was on the glass, both with the supplied 3 strips.  The window tape had been losing its grip within the first year so I used 3M command strips that lasted much longer. Looking for installation suggestions: how would you mount the main sensor body on the glass?