The table tennis racket is composed of three parts: the bottom plate, the rubber skin and the sponge. The reasonable combination of the three determines the quality of a racket. We often refer to the terms of table tennis rackets and sponges, such as: "speed", "control" and "elasticity" "soft and hard bottom plate".
In fact, these indicators have no industry-unified values, but the major manufacturers have divided themselves in order to be able to use for reference when consumers buy.