This product is suitable to apply in acid and alkali contact environment such as phosphatic fertilizer manufacture and making salt by seawater desalination. Cover layer adopts combination of rubber and plastic filled with excellent acid-resistant and alkali-resistant inert material which takes more advantages compared with neoprene acid and alkali-resistant belt. Frame material adopts EP canvas which makes the performance be more reliable than belt with cotton canvas core. It is made ringlike generally.