IP = Ingress Protection. Indicates the level of protection for the housing against external influences, in compliance with DIN EN 60529. The first figure describes protection against foreign bodies, the second figure describes protection against water. The higher the individual values are, the higher the respective protection level is.
Luminous intensity distribution
Describes the spatial dispersion traits of a light source.
Also called radiation angle, describing the angle between two points, at which luminosity falls to 50% of the maximum value.