Antique electric lamp light shade holders, 3 UNO 3 1/4

3 antique brass shade holder UNO (go on sockets with the fine threads at the bottom of the body), 3 1/4 fitter size. Do not have the 1912 patent date, instead stamped with the UL Lab igsignia so most likely from the 20s. Original screws, conditionwise these look as to never have been used.