If you don't have these rings, then you most likely have threaded handlebars. [substeps] Threadless handlebars will also have additional screws on the back of the handlebars.
[header] How to raise road bike handlebars [title] Find the spacers above and below your handlebar stem. [step] Your handlebar stem is the rod that the handlebars connect to. If you have a threadless system, you should see spacers, or plastic rings, wrapped at the top and bottom of your stem.