For your consideration, I offer a group of bottom caps which would go on a brass or nickle oil lamp for a hanging wall bracket. See the last picture for just an example of where these would attach. Very often, in current days, this piece may often be missing. It has a screw that attaches it to the bottom and sometimes these get loose and the cap falls off if packed and moved too many times. These caps come in various sizes and it is rather confusing to try to give accurate measurements and hard to figure out without have the item in hand but a good lot for an oil lamp collector to have on hand. These are all old, probably circa late 1880s-1890s. They are all brass, with one being nickle plated brass. There are two that have the same embossed floral and leaf pattern and one is brass, the other is the nickle one. I turned the caps to the inside to measure. The top of the inside rim on these is 3 1/2 inches. With the font inserted, resting on the lower inside of the cap, the cap measurement inside bottom is approximately 3 3/8 inches. The cap with the ribbed pattern has the same measurements. There is one brass larger cap which measures 4 inches on the top of the inside rim and 3 3/4 inches on the inside bottom of the cap. There is a plain one and I am not sure exactly what it goes on but it is made similar to the others with a thump screw plus two inside brads to slide into the font rim. This one is more dish shaped and hollow in the center. It measures 4 inches on the top inside rim and 3 1/4 down inside the cap. These have been accumulated over over fifty years of collecting. They are old, dirty and need cleaning in most cases but are in good shape as described. The price is for the lot.