It can be our duty to satisfy your preferences and successfully serve you. Your pleasure is our best reward. We have been looking forward to the go to for joint expansion for AC Bridge Experiment, Lambert"s Cosine Law, Para-Magnetism, Photoelectric Characteristic,Three String Pendulum. We welcome new and old customers from all walks of life to contact us for future business relationships and mutual success! The product will supply to all over the world, such as Europe, America, Australia,Portugal, Egypt,Germany, Ghana.We set a strict quality control system. We have return and exchange policy, and you can exchange within 7 days after receive the wigs if it is in new station and we service repairing free for our products. Please feel free to contact us for further information if you have any questions. We are glad to work for every client.