... 5; 1)name:day and night board lens;2)focal length:4mm;3)aperture:1/1.8;4)mount ... of Monofocal fixed iris lens,monofocal manual iris lens,monofocal auto iris lens,Manual vari focal manual vari focal lens,Manual ... vari focal auto iris lens,board lens,anto ... auto iris monofocal lens(DC)etc. As to the fixed focal.There are 2.1,2.5,2.8,3 ...