If you're into mask making or any kind of DIY crafts that need adjustable straps, this stretch cord set is exactly what you need! You get 12 pieces total - 6 black and 6 white cords, each 7.5 inches long and 5mm wide. The spandex material is thin enough to be comfortable behind your ears but durable enough to hold up through repeated use. The best part is the pre-attached silicone cord locks that have two different sized holes (3.5mm and 1.6mm) so you can adjust the tightness perfectly. No more struggling with separate pieces - these are ready to sew directly onto your projects right out of the package. The flat design sits comfortably without digging in, and the stretch gives you a secure but gentle hold. Perfect for face masks obviously, but also great for other crafts like hat straps, costume accessories, or any project where you need adjustable elastic. The black and white colors coordinate with pretty much any fabric. Whether you're a serious seamstress or just getting into DIY, these pre-assembled cord sets save you time and frustration. The quality is much better than those cheap elastic bands that lose their stretch quickly.