DALI dimmable Biro Circle LED ceiling lamp in ring shape The ring-shaped Biro Circle LED ceiling light offers a very wide beam angle, achieving good, wide-area light distribution. Nevertheless, the integrated LED module does not dazzle, as its cover is opal white. The Biro Circle ring luminaire is made of aluminium, steel and first-class plastic. The workmanship is just as high quality as the materials used, which is reflected in its elegant design. A particularly attractive, slightly futuristic overall appearance is created when several Biro Circle lights are combined in large rooms - chromaticity tolerance (initial MacAdam): 3 - very wide beam angle (108 °) - glare-free thanks to opal cover - includes ballast - externally dimmable via DALI