The HAWK interceptor missiles would be an upgrade to the Stinger missile systems - a smaller, shorter range air defense system - that the United States has already sent to blunt Russia's invasion.
The Biden administration would use the Presidential Drawdown Authority (PDA) to transfer the HAWK equipment which is based on Vietnam-era technology, but has been upgraded several times. The PDA allows the United States to transfer defense articles and services from stocks quickly without congressional approval in response to an emergency.