Crystal clear shatter-proof films provide protection against damage to person and property, and can be retrofitted to almost any glass surface. Window panes broken or just cracked due to accident, burglary and material defects present a high risk of injury. These crystal clear and almost invisible security films are available in thicknesses from 100µ to 190µ. The choice of film thickness depends on these factors: a) what kind of damages are expected and b) how to calculate them. As a rule of thumb, shatter-proof films of thickness 100µ are recommended for glass surface of maximum 0.75 m² and 190µ for areas above that (1000µ = 1mm).