The HEPCO&BECKER tank ring for fastening tank bags is a big advance for attaching tank bags to the motorcycle.
The problems associated with positioning the tank bag are eliminated by magnetic centering.

The side ribs attached to the magnets also mechanically secure the tank bag.
When the lock is released, the poles of the magnets match and the tank bag is released from the attachment.
The tank bag‘s base plate shields the magnetic field of the tank ring‘s two permanent magnets, so that credit cards and electronic devices cannot be damaged. 

Facts:

• special powder coated metal tankring
• two high power magnets which secure the tankbag on the ring
• every tankbag by HEPCO&BECKER can be fitted; but depends also on bike specific tank-lid positioning and handlebars; please check manual for more info and limitations
• For the bike specific Norden tank ring tankbag attachement Hepco&Becker recommend the Street Daypack 2, Tourer M, Royster tankbag and Royster Daypack for optimum fit.
• Tankbag "Daypack small 640804" does not need tankring 

Note images show addtional accessories fitted and are for illustrative purposes only.