This standard specifies two methods specifically for determining the surface tension of natural latex, synthetic latex, prevulcanized latex, and compounded latex. The first is the platinum ring method, the core principle of which involves measuring the maximum force required to detach a platinum ring from the liquid surface, and it is suitable for latex with relatively low viscosity. The second is the platinum plate method, which calculates the surface tension by measuring the force exerted on a platinum plate when it reaches wetting equilibrium with the liquid. It is explicitly stated that this method is not applicable to latex containing cationic surfactants. The testing instruments involved in the standard are primarily surface (or interfacial) tension meters designed based on these two mechanical principles.