Riverside has time clocks available for sale. A time clock originally was a device where one put in a punch card to mechanically record the in and out times of an employee, and the basic principle and intention of this system has remained the same. The newer versions of time clocks use biometrics for identifying and recording people, based on their unique biological imprint, such as hand print, finger print, finger vein, palm vein, facial recognition, iris or retina. This can be used to track the number of hours an employee puts in, whether he comes early or late, and his general productiviy when cross-linked with the work done.