B: 4 digits LED Display Features: 

1)    various size and color available

Digit height: from 0.28" to 20" (0.28", 0.3", 0.36", 0.39", 0.4", 0.5",0.52", 0.56",0.8", 1.0", 1.2", 1.5", 1.8", 2.3", 3.0", 4.0", 5.0", 8.0", 10", 12", 16", 20".)

Various emitting colors: red(640nm),yellow green,(572nm),pure green(525nm),yellow(590nm),blue(430nm), pure blue(470nm). 
2)  many application. 

household electronics-----DVD/VCD player, induction cooker, micro-wave oven,air-conditioner,e-fan,washing machine,soya-bean milk machine,etc.

factory/company equipment-------instrument panels, digital read out display,calendar,smart meter,electronic scale,etc.