Above is a Anti Burglar device as found in some old Ratner safes. Anti burglar devices are found in most safes and vaults. Modern anti burglar devices include glass or a thermal link to stop.an inexperience thief, Locksmith or Safe Engineer from opening the safe or vault. If these devices are set off by an inexperienced person. Then the safe will lockup further and require a real Safe Engineer to come and open it. At Key Elements Safe Engineers we specialise in opening safes and vaults and have done so for over 25 years. kelocks1@gmail.com