They work a little time, you need to clean and configure. I did not check all the features. Diameter 8.5 cm. After you receive the goods. I do not check for and do not know if there is any issues that are not visible on outer case. You have collectible item that increase in value over time & perfect gift idea as well. If you have any questions or require further information concerning the item, feel free to contact me. Thanks so much for taking the time to come over.