What's the sign that they're holding at the side of the track.

The p n l things with numbers on it, sorry, I'm new to this
Submitted April 28, 2018 at 03:21PM by Muazrozlan https://www.reddit.com/r/motogp/comments/8fk6cw/whats_the_sign_that_theyre_holding_at_the_side_of/?utm_source=ifttt