They are approximately 3/8" in diameter and the tube is 28 7/8" long.
Most of my windows (6 lights)weight 15lbs but a couple of smaller 4 light windows only weight 10 lbs. They both have what appears to be the same spring. The nylon tip appears to be a faded yellow or off-white color.
I need the tool that winds the springs up and sets the hooks into the nylon guide.
