This is absolute trash. Poor quality and bad assembly. The sockets are made of porous porcelain with cracked threads, which prevents the socket ring to remain straight as it is screwed to the socket. Additionally, the socket itself is not properly secured to the lamp and screwing the socket ring to the socket causes the socket to detach itself from the lamp - see picture. It took my electrician over an hour to fix them. These lamps are sold as single unit. I bought 2 and both were of very poor quality. I can only conclude that this is not a fluke.