As the market is flooded with rubber joints, it's inevitable to encounter some sellers who sell substandard products. If you're not familiar with how to assess the quality of rubber joints, you might end up buying a faulty one and discover it only after use. When trying to return it, if the seller agrees, it's just a waste of your time running back and forth. The color of the rubber joint is a key indicator; particularly bright colors are not good signs for a rubber sphere. A good rubber sphere has a natural sheen that's black with a hint of natural brightness, reflecting a genuine rubber color.

Secondly, a good rubber sphere should feel smooth and have high flexibility when touched. If the surface of a rubber sphere is not smooth or has any破损, it is not a good rubber sphere, especially when examining the interior. It is crucial to ensure the inside is smooth, as we know the medium flows through from the inside. A smooth sphere guarantees the medium passes through without delay or accumulation, and prevents erosion. High elasticity is primarily achieved through the use of good rubber, which facilitates movement and is resistant to aging.