7C series trailer is suitable to be used for plain area\mountain area\swamp and hills \farmland and highway transportation etc. Different area environment, trailers of different forms match the tractors of different types. On basis of fundamental type, we have developed the hydraulic pressure self-discharging trailer, improved efficiency the appearance is exquisitely\artistic and unaffected\the structure is rational and compacted, sturdy and durable\be able to adjust the height, the machines are advantageous and reliable, they are good assistant of mountain area friends.