The lamp looks very fine. The processing will also fine. However, the change of the lamps is almost a patience and Geschciklichkeitsspiel and is almost unthinkable when attached to the ceiling on the circuit. You have to use the lamps a porcelain lead with a rotation mechanism without hitting the slots to be able to see (be obscured by the light source). This effort is really unacceptable and justified most constrained by the low price of the lamp.
