The led signal towers ld6a from idec have an unusual oval design while in conventional signal towers the translucent calottes are directly laid on top of each other they are separated in the ld6a series by opaque plastic from each other which provides in addition to special lenses with triple refraction for better detection of the signal states the labelling of the individual signals on the intervals is also possible the base modules are also available with blinking light and acoustic alar