In mechanical time clocks, this was accomplished by inserting a heavy paper card, called a time card, into a slot on the time clock. When the time card hit a contact at the rear of the slot, the machine would print day and time information (a timestamp) on the card. One or more time cards could serve as a timesheet or provide the data to fill one. This allowed a timekeeper to have an official record of the hours an employee worked to calculate the pay owed an employee.