Constrution Features:
1,Positive pull the chain ,woller blinds down,reverse the chain ,head only unlock,roller blind automatically up.
2.The system is equipped with retarder,and the roller blinds rises automatically and stably.
3.Roller blinds can be stopped at any height .
4.By adjusting the number of pre tightening turns of boost spring,the rising speed of roller blinds can be adjusted 
5,1:1.5 reduction ratio is  adopted for the clutch making ,which makes it easier to the chain.
6.The system is equipped with a limiter,and the roller blinds will automatically stop when it rises/fall to a fixed position

Performance Features:
1.Min width:0.95mm
2.Max Height 3m
3,Max load 3kg