Vintage pendant lamp by Carl Thore for Granhaga Metallindustri Swedich

Pendant light designed in the 60s by Carl Thore for the Swedish lighting company, Granhaga Metallindustri A B. Aluminum structure (with copper-like color bath) that draws two cones (in the shape of a diabolo and the lower one being larger) and a diffuser grid (removable) at the base. Mention the optical effect produced by the ring, located in the narrowest part where both cones meet, which when the lamp is turned on causes the light to bounce off the outer surface of the entire lamp.