The term 'safe crackers' refers to people who specialize in opening locked safes without the use of a key. The job title for these professionals is 'UMP, ' which is a four-letter acronym for 'unlocker of mechanical and physical security.' Umpers are highly skilled individuals who use a variety of tools and techniques to open safes, including lock picking, drilling, and manipulation of the locking mechanism. They are often employed by banks, law enforcement agencies, and private security firms.