This is a multi-pattern tube condensor mic.
The switch that has a 0db -10db markings is just a attenuator.
Set to 0 db means full output and -10db means that the output is reduced by 10 db. The switch marked – /- is a low frequency roll off switch. Set to – means that the full frequency of MF’s recording mic is being sent to the preamp and set to /- means that lower (bass) frequencies are being reduced at the output.
The three position switch controls the polar pattern of the mic.
The 0 position is the omni mode and the mic hears sounds equally from all sides.
The 8 mode (figure 8) picks up sound equally from both from and back, but rejects sounds at both sides of the mic.
The last one is the cardiod mode and the mic picks up sound best from the front and rejects sounds from both sides and the back.
I would suggest googling “microphone polar patterns” to learn more about the uses for each pattern. If the mic came with a manual, that should also help.