Set MUI Select width?

I am trying to set the MUI Select component's width. For this I have to provide a class to the FormControl component, such as mw-120 which links to a CSS class defining the min-width of 120px.

Material UI Select component:

<FormControl className='mw-120'>
    <InputLabel htmlFor='selected-language'>Language</InputLabel>
    <Select value={this.state.selectedLanguage}
            onChange={(e) => this.onLanguageChange(e.target.value)}
            inputProps={{
                name: 'language',
                id: 'selected-language',
            }}>
        {menuItems}
    </Select>
</FormControl>

CSS class:

.mw-120 {
    min-width: 120px;
}

While I would expect the size of the Select component to now have a width of 120px minimum, the component remains exactly the same after rendering, as shown in the following picture. In other words, it is to narrow. The width is not big enough. The width should be greater than the label Language.

An element analysis within the Chrome Developer Tools has shown that the main DIV element of that component has a class .MuiFormControl-root-234 that contains min-width: 0;, and it is located/ranked higher than my .mw-120 class. I guess this overrides my .mw-120 class, right? Is there any other way to influence the width of the Material UI Select component? There are no helpful examples of influencing the width of this component on the Material UI Select component page.

For potential re-use, the official doc samples accomplish this with makeStyles like this:

import { makeStyles } from '@material-ui/core/styles';

const useStyles = makeStyles((theme) => ({
  formControl: {
    margin: theme.spacing(1),
    minWidth: 120,
  },
}));

Then useStyles generates class names like this:

const classes = useStyles();

Then add to your FormControl component like this:

<FormControl className={classes.formControl}>

Demo in Stack Snippets

<!-- begin snippet: js hide: true console: true babel: true --> <!-- language: lang-js -->

const { FormControl, InputLabel, Select, MenuItem, makeStyles } = MaterialUI;

const App = function () {

  const useStyles = makeStyles((theme) => ({
    formControl: {
      margin: theme.spacing(1),
      minWidth: 120,
    },
  }));

  const classes = useStyles();

  return (
    <div className="App">
      <FormControl className={classes.formControl}>
        <InputLabel id="demo-simple-select-label">Age</InputLabel>
        <Select
          labelId="demo-simple-select-label"
          id="demo-simple-select"
          value={''}
        >
          <MenuItem value={10}>Ten</MenuItem>
          <MenuItem value={20}>Twenty</MenuItem>
          <MenuItem value={30}>Thirty</MenuItem>
        </Select>
      </FormControl>
    </div>
  )
}

ReactDOM.render(
   <App />,
   document.getElementById('root')
);

<!-- language: lang-html -->

<script src="https://unpkg.com/react@17.0.2/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@17.0.2/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/@material-ui/core@4.11.3/umd/material-ui.development.js"></script>

<div id="root"></div>

<!-- end snippet -->