This product consists of 20 pairs of flash cards based on the topic Heat Transfer –Conduction, Convection & Radiation. You can print back to back and laminate them. These cards can be used after the completion of the topic which helps the class to understand the three modes of transfer of thermal energy. When I did my revision for this topic using these flash cards, my students gave a good feedback. Hope you find the same for your class! Please let me know your feedback!