Alled's LED bulb would be useful in Car, Vehicle, Caravan, Marine, domestic applications etc. Most used for replacing G4 halogen bulbs. It is brighter than regular LED bulbs and has wider field of view.
You are purchasing single piece of LED G4 Bulb, the term of 18-SMD only means the quantity of LED chips on its circuit board.
This G4 is only uesed in application environment with 12V DC. If you want to install it in your home environment, you need a transformer from 100-240V AC into 12V DC.