Protective Housing Labels are required on all panels or connections which when removed, opened or displaced will give access to radiation in excess of Class 1. The class of this label is determined by the class of the laser radiation accessible once the panel is opened (e.g., a panel on a Class 1 laser product, which when removed gives access to Class 3B laser radiation will require a Protective Housing Class 3B label).
The WIFE is an automatic LED sign that shows which laser wavelengths are in use in the laboratory, so you can select the correct laser protective eyewear before entering.
