You're looking at a rare set of 3 matching antique "Eye Comfort" X-Ray shades dating to approx the 1910s - 1920s. I've had many styles of mercury glass pendant lights in the past but I've never seen this particular shape before.
They do not appear in the 1920s X-Ray catalog I have. Each has its steel mounting bracket that holds the glass shade in place.
These pieces were stored in a warehouse for many years and are now being made available for the first time. They show wear commensurate with age including paint splatters, dirt, paint loss, marks, scuffs etc; which all add to the character and authenticity of these lights. Measurements: 10.5" deep x 10" wide x 7 tall (inc the bracket). Please check out my other Industrial/ Mid-Century listings.