Gary,
It looks like the actual fitting for the sender is installed in an adapter. Unthread the sender from the adapter and then check thread sizes of the sender versus your intake. If it does not thread right in, you may just need an adaptor to go from 1/8 to 1/4, for example. The gauge manufacturer can supply the adapters or your local hardware store may have something in brass that will work.
My
oil temp sender is like this as well as my water temp.
Good luck,
Gary