CRC basically a card but its uses in many fields which is mentioned are there, Its stands for Class, Responsibility, and Collaboration. A CRC card is nothing more than a 4x6 index card. This is a very simple, low-tech device allows you to work with other people in understanding the primary responsibilities of our initial set of classes. We assemble a stack of blank 4x6 index cards and meet around a conference table for a series of CRC card sessions. CEC cards are used to identify classes, responsibilities and collaborations between the objects in an object-oriented system.