This Slip Uno Adapter Converts your Standard "Spider" Lampshade to fit on Slip Uno Lamp Base. Uno opening is 1 7/16" which is the most common size, so be sure to measure your bulb socket to make sure the diameter is less than 1 7/16". Slip Uno adapters are made to fit directly over a plastic lamp socket found on lamps usually purchased at many popular retail stores. Slip Uno fitters are generally held in place with a plastic threaded washer. Uno fitter shades are difficult to find, so this adapter lets you use standard washer fitter shades on your uno lamp base. This adapter attaches directly to the harp, allowing use of nearly any replacement lamp shade. Harp is 6" tall and the height from the bottom Uno ring to the top plate is 6", so this fitter works best with shades that are about 9" tall. Polished brass finish.