When it comes to personal safety, there are plenty of things that we can buy to help keep ourselves safe in public. For example, you can buy mace/pepper spray to fend off attackers, or there are also whistles and devices that emit loud and shrill noises to deter attackers or to bring attention to yourself.
However, over in Japan, a stationery company based in Nagoya by the name of Shachihata has started to sell something called the Anti-Nuisance Stamp. This is a stamp that uses UV ink that marks the person it has been stamped on, similar to how some clubs use UV ink mark patrons who enter their establishment.
The idea of the stamp is that it will allow women to quickly stamp their attackers without them necessarily knowing about it. After which if the women were to report the incident to the police, the stamp can help identify the groper. It appears that these stamps have proven to be a hit where the company has sold out of its entire batch on the first day of it going on sale.
Accoridng to ubergizmo