Haul-off unit is oscillating reverse by horizontal±180°.Its structure is reasonable, so it economizes lots of energy and it is easy to maintain.By means of the reversing haul-off unit, films can be produced without requiring rotating diehead, so the structure of diehead is simplified. Reversing haul-offunit eliminates many problems of lingchannel for the rotating diehead, diffficult sealing for the melt, compound leakage being easy,unsymmetrical heating, difficult maintenance, macro film tolerance and so on Haul-off unit reduces the drgree of difficulty for recipe of the multi-layer coextruded product and production technical processing control, If the blown filmline is withIBC (Internal Bubble Cooling system), itcan produce film with the quality of more high-grade transp-arency and better all round performance.The produced film is very flat,reel is high-quality by theuse of reversing haul-off units. The film can meet the demand for the high-speed printing.