It is not a high quality product. The Neon tiny bulb can move inside the housing, if you pull the wires, the bulb moves backwards and it's light is dim. To solve the problem: push the 2 wires inside, thus the bulb will move to the front, put a drop of glue to fix the wires' position.
Green lamps are actually orange neon bulbs with green plastic covers, so they look a weird color when illuminated. Stick with the red color ones which look fine.