No, it is a wrench with a completely round head on one side.
Do up or undo a nut where a ring wrench or socket might otherwise not fit.
Deep or if you can't get one long enough, a box end wrench
A box wrench has that feature.
Clearances between the cotter and slots in the rod end and socket allows the driven cotter to draw together the two parts of the joint until the socket end comes in contact with the cotter on the rod end.
The function of a wrench depends on what type of wrench it is. In general, small flat wrenches have two 'flats' that are sized to particular bolt or nut sizes.These wrenches are used to loosen or tighten nuts onto bolts. The crescent wrench is able to be adjusted to many sizes of nuts and are handy to have in a tight corner when you don't know the size. Ratchet wrenches are used to do up or loosen nuts quickly where movement may be restricted and you have to re-seat an ordinary wrench after each partial turn. Box wrenches have round heads, able to completely encompass the nut and are very useful where nuts are rusted or otherwise extremely tight. Pipe wrenches are usually larger jawed wrenches used to grip large pipe nuts and pipes themselves in plumbing work.
Adjustable Wrench , open end wrench , box wrench, socket wrench, monkey wrench
A box end wrench goes all the way around the nut, like a slice of a socket. An open end wrench grips just on two sides.
A 15mm socket or box-end wrench will do it. Be sure to use a 6-point instead of a 12-point, in case the drain plug has been tightened beyond belief. I speak from personal experience on an older Chevy
Wrenches come two ways, open ended and box end. Open end are just a U shape on the end. Box end go around the nut or bolt. If you were to slice a quarter inch off of a socket that is what the end of the wrench would look like.
You need a 9/16" box end wrench for the drain plug. The filter requires a special socket to remove the cap. I used to use a 1 1/4" open end wrench until I bought the socket from Snap-On.
I did them on my 2003 and it wasn't complicated. The caliper bolts are 15mm, which surprised me and sent me to buy a box-end wrench that big. They are tight, so have a long wrench to get started, then a socket will do the rest. You can pry the old pads back by inserting a screwdriver in the caliper slot on top, then remove the caliper, swap out the pads, and replace it. I did both wheels in an hour once I had the right wrench.
Use a proper size box-end wrench or socket to remove the oil drain plug
Assuming you want to drain the engine oil, the original drain plug would require a 15mm box end wrench to remove it.
You put the end of a 3/8 socket wrench on it (with no socket).
With a boxed end wrench or socket, never with an open end wrench.
Open end, box end, with 6-point or 12 point box end, flare end, ratcheting end-wrench, Crescent (or aka adjustable), crowsfoot, pipe wrench and more
Do up or undo a nut where a ring wrench or socket might otherwise not fit.