came here looking for that info, and he fails to mention it

On a same vehicle kia spectra 2008

@@asimwaqar6317 it is a ⅝ spark plug socket. But depending on the brand of tool you might need a 16 mm spark plug socket. It is not exactly the same and you might not find it every store. ¹³/¹⁶,⅝ and 16 mm are the 3 spark plug sockets I have used for 20 years. I got them from Snap On. The 16mm is the rare size. People argue that the 16 mm doesn't exist, but on motorcycle engines if you don't have it the ⅝ just won't fit in lots of new bikes. Also some cheap spark plug sockets have a thicker wall and a quality spark plug socket will be stronger metal but doesn't need to be super strong because it is for removing spark plugs which can be right but nothing that a quality thin wall tool can't handle. And also the rubber inside to hold the plug will last and perform for years instead of falling out or swelling and getting stuck on the socket and you pull the extension out and the socket is stuck on the plug. It might cost 2 or 3 times what an average spark plug socket cost, but it is nice to have a quality tool instead of working with a 8$ junk tool. I think the Snap on socket might run 40 or 50 bucks. And it sounds like a lot. If you go to a repair shop and ask the manager if the he has the phone # for the Snap On dealer that supplies there shop then call and I would expect he would be able to have it to you at the shop in the next week. They usually stop a shops once a week. That is part of the price of the tool is that they come to you to service and supply tools and you don't got to them. But that is the tool I use I haven't seen a 16mm spark plug socket from any company except the tool truck brands. Cornwell is another one I recommend, although not as well known Cornwell is in some ways a better tool than SnapOn. Just less flashy and more business and durable in my experience. That's it . That's my tool rant !Hope it helps.