Using these LED bulkhead letter box lights is easy. First, make sure to have a licenced electrician install them as per the instructions in the box. They work well with an input voltage between 100 - 240V AC 50/60Hz. You can use them with 2 - way switching or pair them with PIR or Microwave sensors. The number stickers in the package can be used to add a personal touch. When it comes to maintenance, keep them clean. Wipe them gently with a soft cloth. Avoid using them in harsh weather or heavy rainfall unless they are properly protected. This will help ensure the 3 - year replacement warranty remains valid.