42mm is a standard socket. If you mean "what SAE socket fits," none of them do. BTW, what are you trying to get off that's got a nut that big on it?
1 1/16" standard is closest to 27mm
It is: 42mm = 4.2cm
Ball and socket
The part of the tooth that fits into the socket of the jaw(mandible) or maxilla(for upper teeth) is the "root" of the tooth.
Socket
Any battery socket that it fits.
Fits socket 7 boards.
No, you cannot use a metrc socket on a standard socket wrench. These are two different systems of measurement and are not interchangeable.
Spark plugs use SAE and not Metric. The one that fits it is the one that fits it.
Any battery socket that it fits.
18MM
11/16" (18mm) deep well socket