FAQs How are the light up numbers powered? They are all mains powered using a standard mains connection. ​ How many sockets do I need? Each letter/prop has a separate plug, however we can provide sufficient extension leads to enable us to connect the letters to the mains using just one socket. ​ Are the letters/props suitable for outside use? We do not recommend that the light up letters are used outside for safety purposes. We can however make exceptions should you have an event manager present all day that would be able to move them immediately should the weather change. They would also need to be in a very stable position protected form the wind. We also would not recommend this for a large number of letters.