The NMJ glasses strap is made of silicone material, so it is lightweight and stretchy, so it is comfortable to wear. In addition, the string of the glasses can be easily installed by anyone, just inserting them into the holes on both ends of the body. Comes in a 4-piece set that is blue, purple, light blue, and black, so you can change it according to your mood, or share it with your family or friends.