optional 3,4,5,6 digits setting code appearance on screen or not mechanical override key time dilay before opening (optional 0-24 minutes setting) low battery announcement&Low energy consumption Specially designed space for lap-top computer Single-time molded case and unique spray coating technique Keypad auto lock after consecutive 4 wrong code or card time dilay before opening (optional 0-24 minutes setting) 100-time opening records printable Offering CEU(computerized emergency unit), which has multifold functions: as the electronic override key read and export safes last 100 times door opening records as the emergency power if the safes batteries were run out support any kind of credit cards issued by banks all over the world