Bunch Filament (G.B.)
A filament (usually of multi-vee formation) in the form of a segment of a hollow truncated cone or hollow cylinder, generated around the axis of the lamp and embracing an arc of a circle greater than 180 degrees but not fully closed.
Note: For the French and German terms applicable, see 2-3-210 and 2-3-215.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM