Halo had its first serious trial at Spa on Friday morning with Nico Rosberg putting in the first laps in anger.
Mercedes, Force India and Toro Rosso all ran the cockpit protection design for the first time while Daniel Ricciardo put in a second run for Red Bull Racing.
Rosberg pace-setting time in FP1 was done with Halo attached to his W07. He posted a 1:48.348.
The German was the only driver to put in consecutive laps with Halo as other three; Nico Hulkenberg, Carlos Sainz and Ricciardo, only did brief runs.
Formula 1 has delayed the introduction of Halo, or any other cockpit protection device, until 2018 after deciding that more testing and development needs to be completed.