Tensile Strength is the force required to cause the rupture of a rubber material. Normally expressed in Megapascals (Mpa). A solid rubber with a higher Mpa reading would normally indicate a better quality of material. This is normally measured with a Tensometer at a predefined thickness and size and is generally measured to ASTM D412.
Care should be taken in comparing different manufacturers test data for Rubber Sheeting with high tensile strength to ensure that the test method is consistent.