F in a Pentagon (F im Fünfeck)

A registered testing body applies the mark after confirming a specific model's output stays within the legal limit, and the mark travels with that model rather than being something an owner can self-apply after the fact — a gun without it, regardless of its actual measured power, doesn't get the lighter legal treatment.

Retailers selling into Germany generally only stock F-marked models for that reason, and the mark is one of the first things worth checking on an import or grey-market purchase, since an unmarked gun otherwise under 0.5 joules can still be treated more restrictively under the law. This is general information, not legal advice — always confirm current requirements with your national authority and your field before you buy, carry or play.

Second-hand marketplaces are where an unmarked or dubiously marked gun most often turns up, so buying used specifically from within Germany, ideally with the original packaging showing the mark, is the safer path for a first purchase.