Round bottom base measures 8 3/8 inches across. Top heat ring/shade holder approx 3" or 3 1/8". Please VIEW ALL PHOTOS as they are a very important part of the description.Condition shows charming age-appropriate wear and patina, including small finish losses here and there notably (a) on the edges of the round bottom base and also (b) on the center column where no doubt many hands have grabbed hold of it during the past century! , plus possibly a few scuffs, scratches, nicks here and there as one would expect to find in a 100+ year old antique lamp. One of the six holes is original from Wilkinson (where a tiny Wilkinson set screw might go in if I had one, however no screw is included). The other five will be covered when a Wilkinson shade is placed on top of the shade holder ring. I always recommend rewiring old lamps before using them. This lamp is now functional and I have been using it several times, however, I cannot vouch for this antique/vintage turnkey socket and I cannot guarantee somebody else's wiring. It is always a prudent decision to have old lamps checked out by an electrician before you use on a regular basis. Remember: Better to be safe than sorry! The item "25 WILKINSON Lamp BASE # 251 w Top Ring slag leaded stained glass, Handel era" is in sale since Thursday, October 12, 2017. This item is in the category "Collectibles\Lamps, Lighting\Lamps\ Electric\Table Lamps". The seller is "890fravita90" and is located in Hasbrouck Heights, New Jersey. This item can be shipped to United States.