In Germany, paintball is restricted to players over 18 years of age. Paintball markers are classified as weapons that do not require a license or permit; they are legal to buy and use, but restricted to adults. Markers are limited to a kinetic energy of 7.5 J. Tampering with the marker to increase muzzle velocity above 214 fps can lead to confiscation/destruction of the marker and a fine. All paintball markers sold officially in Germany must be certified by the government "Physikalisch-Technische Bundesanstalt" (PTB) (Federal Physical and Technical Institute) to operate within these limits and must have a registered serial number and an official stamp on the firing mechanism. In May 2009, reacting to the Winnenden school shooting, German lawmakers announced plans to ban games such as paintball as they allegedly trivialized and encouraged violence but the plans were retracted a few days later. Most Indoor-Paintball-Areas in Germany have a strict "No-Mil-Sim"-Policy, meaning that no camouflage clothing or real-life looking markers are allowed.