? Service: 8 hours email reply, 30 days refund and 12 months warranty for quality. Please contact the seller if you have any problems. ? Stretchy & Flexible: This braces rubber bands allows patients to maintain a full range of motion during talking, yawning, and other normal jaw functions. ? Simple & Effective: The unique elasticity of the orthodontic rubber bands helps to adjust the occlusal relationship between the upper and lower teeth. And it can increase the traction required for the whole tooth more flexibly. ? How It Work: Dental rubber traction bands promote the movement of teeth through external force and is one of the auxiliary props to increase traction. It can be used to correct most types of bite problems (overbites, underbites, open bites, and crossbites). ? Specifications: Annhua braces rubber bands is heavy force 4.5 Oz, 1/4" size and clear color. The type of rubber band to use is chosen by the doctor according to the condition of your teeth.