Grenade, Concussion (5e Equipment)
From D&D Wiki
Martial Ranged Weapons
Also known as blast grenades, these are anti-personnel devices with a much higher yield, but with a thinner case, and therefore fragmentation potential compared to the typical fragmentation grenade. They are primarily designed to damage, daze or otherwise stun its targets with overpressure shockwaves.
As an action, you can throw a concussion grenade at a point up to 60 feet away. Each creature within 20 feet of an exploding concussion grenade must make a DC 15 Dexterity saving throw or become stunned until the end of its next turn. Creatures within 5 ft. of the grenade take 5d6 thunder damage. On a successful save, a creature takes half damage and isn't stunned.