Euro key

Euro key is a locking system which allows people with physical disabilities to use locked accessible toilets across Europe. It was introduced in 1986 by the CBF Darmstadt in Darmstadt and environs.
People with certain disabilities can order a key online by providing medical documentation and paying a fee.
The Euro key is now widely used throughout the following European countries: Austria, Bulgaria, Czechia, Denmark, Finland, France, Germany, Italy, Liechtenstein, Norway, Portugal, Romania, Slovakia, Spain, Sweden, and Switzerland. There are approximately 12,000 locks that use the Eurokey.