This product is different from a normal zipper in that it uses a double zipper with two pull tabs that can be opened and closed from the top and bottom.
Compared to regular zippers, it may feel stiffer or more difficult to open and close.
When opening and closing, please note the following:

• Please align the top and bottom sliders before use. Lower both sliders to the bottom and check that they are aligned. Adjusting the slider grooves so that they are straight will ensure smooth opening and closing.
• If the zipper feels stiff, forcing it open or closed can damage the fabric or break the zipper, so make sure the grooves on the top and bottom sliders are aligned and the zipper is all the way to the bottom. Then hold the zipper pull and open and close it slowly and carefully.