Rings in coloured anodised aluminium starting from an internal diameter of 2.0 mm up to an internal diameter of 11.0 mm
These are the most resistant types of rings, suitable for birds with strong beaks. The surface is bare metal, not coloured.
Rings made of coloured anodised duralumin, a more resistant metal than standard aluminium. The colour is established annually by the C.O.M
This range includes larger rings, with internal diameters of between 13.0 mm and 27.0 mm.