The heat shrinkable material used in automobile wiring harness is expected to further improve the market share in China. At present, China's domestic hot shrinkable materials are still very low in the automobile manufacturing market, only about 20%, the 80% of the global market is occupied by the United States Ryan and Japanese Sumitomo. With the overall approval of the automotive industry certification and the advantages of the cost, the market proportion of automobile heat shrinkable sleeves is expected to be further improved. At present, the price of double wall heat shrinkable bushing used in domestic cars is only 20%-50% of American Rui Kan and Sumitomo Sumitomo. According to the analysis of the current supply of automobile industry in China, if all the heat shrinkable sleeves are made in China, the average use value of each car is about 100-200 yuan, and the price of the heat shrinkable casing used abroad is 200-500 yuan. It is assumed that the market share of heat shrinkable cannula in China is up to 40%, and the output of heat shrinkable sleeves in China will reach about 4 billion 200 million in the world's annual output of 70 million units. At present, the gross profit margin of heat shrinkable bushing is between 40-50%, which is higher than the average level of the industry.