Product review (1 stars): Wrong cord length, poor quality pulleys...do not buy.
As others wrote this part is not an OEM replacement part...the cords are 1.5" shorter than the stock parts and stretching the spring to fit increases the preload so much the door will not stay open.  I ended up bending nails into a "C" to relocate the springs about 1".  To make matters worse the pulleys are disgustingly noisy once installed...it makes a loud groaning noise as the cord runs through the pulley.  I tried lubricating the pulleys with a Teflon spray which did no good.  So it's $11 and the door doesn't fall open like it did before the repair but this is not the part that is advertised.  I suggest you find a place that sells an OEM replacement part and buy that instead.