I have the cordless style (accordion) Levlor blind. It works on the premise that the spring system concealed in the top rail uses a series of gears and wheels to allow you to pull down and push up the blind.
It works except the dimwit who designed the spring system did not think to adhere the springs to their anchor (they just hold there under friction) needless to say the springs slipped loose and unwound and as a result the blind stays in the down position. For the cost the blind looks good quality on the outside but the mechanism looks to have cost a whole topping 50 cents and its junk
Review about: Levolor Blinds.
Reason of review: Bad quality.