#3 nylon coil zippers are lightweight and feature teeth that measure approximately 3mm (1/10 inch) wide when zipped. These #3 nylon zippers do not separate at the bottom; rather, they are closed-ended like a zipper on the fly of a pair of pants. These are one-way zippers (they have one slider). These lightweight zippers are great for clothing like dresses, and also non-garment applications, like change purses.