# getDiameterUnit

> Returns the display symbol for the active diameter unit. mm is locale-invariant; inches is '"' unless locale is 'en', in which case it's 'in.'. Omitting locale preserves the historical '"' default.

> **getDiameterUnit**(`units`, `locale?`): `string`

Returns the display symbol for the active diameter unit. `mm` is
locale-invariant; `inches` is `'"'` unless `locale` is `'en'`, in which
case it's `'in.'`. Omitting `locale` preserves the historical `'"'` default.

## Parameters

### units

`DiameterUnits`

### locale?

`"en"` \| `"pt"`

## Returns

`string`