Lamar Jackson wears a Vettex mouthguard tethered to his facemask. It is incredibly uncommon for a quarterback to wear a lipguard mouthguard because it makes talking difficult. Quarterbacks are the most vocal players on the football field, calling plays, audibles, saying the cadence, etc. Lipguard mouthguards cover your lips and don’t really sit firmly between your teeth. In Lamar’s case, he keeps it tethered to his facemask so he can take it out, say what he needs to say, and put it back. Still, its very unique for a QB to wear this type of mouthpiece.
You can get a Vettex Lipguard Mouthguard for just under $10 on Amazon.