For 5 points and a grenade slot this upgrade adds a new weapon to the unit with one black die per figure at range 1 with Blast.
Concussion Grenades are situationally very strong. If the unit that adds them normally only rolls one white die then Concussion Grenades is a significant upgrade in damage output. Otherwise the main use of this weapon is to take down large groups of troopers behind cover. Keep in mind that Blast is added to the entire attack pool, so even if the unit normally rolls better dice they can throw one Concussion Grenade with the rest of their normal weapons and remove the targets cover completely for the entire unit.
This is a very useful upgrade for units that want to get close to their target and either want to be able to remove enemy trooper unit's cover or increase their damage output at short range (if they normally roll less than one black die). Concussion Grenades are a very strong upgrade on Stormtroopers as it increases their damage output at range 1 and allows them to ignore enemy trooper cover. They are not recommended on Snowtroopers however as Blast on the flamethrower would be redundant. It is also not necessary on rebel troopers as they already roll a black die and tend to want to stay at range, but it can be very useful on Fleet Troopers as they generally want to be close to the enemy and throwing one grenade can remove an enemies cover making the rest of their normal white dice much more effective. Because grenades add a new weapon for 5 points, the more figures in the unit that can use the weapon, the more efficient the upgrade is.
Core Set x4