Electronic stamper prints any combination of date, time & seven different messages: In, Out, Paid, File, Ref, CFMD or RCVD. Print four or six-digit sequential numbers as part of a date / time / message or independently. Design features a digital alarm clock & 200-year calendar. Programmable security code prevents tampering & ensures stamping accuracy. Stamper operates on one 3 volt lithium battery (included) & four AA batteries (sold separately).