Material UI: Remove up/down arrow dials from TextField

I have this TextField in Material UI:

<TextField
      id="contact phone number"
      label="Contact phone number"
      type="number"
      value={this.state.contactPhoneNumber}
      onChange={this.handleChange('contactPhoneNumber')}
      placeholder="Contact phone number"
      margin="normal"
/>

It looks like this:

How would I remove the up and down arrow dials from the TextField?

From the TextField docs, the type prop accepts valid HTML input types. I believe the reason the up and down arrows are present is because you specified number as the type.

Try type="tel" instead, as it seems to be the standard input type for phone numbers.

Here is a reference to the tel type and why it's a good idea to use it. Note that if the current browser doesn't support it, it will fall back to being a regular text field.