FIMO is the oldest brand of polymer clay and is made by Staedtler in Germany. You can learn more about FIMO Soft and Effect here. This clay comes in 2oz bars, except white, which is available in larger sizes.
This variety of FIMO clay is easier to work with than the FIMO Professional line. You can learn more about how to best use and condition FIMO in this article on The Blue Bottle Tree.