"Sticky grenades deal a massive amount of damage to armored targets such as base turrets, generators, and vehicles. This version has been modified for a wider damage spread." In-Game Description
The XL Version acts just like the sticky grenades, flying in an arc when thrown and sticking into enemies and terrain and exploding after a short delay. These grenades do explosive damage meaning they are good against base defenses.
Always use these like the normal Sticky Grenades, but do keep in mind that the XL variant has a massive explosion radius. Throw one and shake a leg, because getting blown apart by your own grenade is not fun. This can be countered by using the Egocentric perk. Combining these with Safety Third perk, you will have a thousand damage grenade that hurts or kills anyone inside a small to medium-large room, meaning they are perfect for clearing out choke-points and defenses. As with the normal Sticky Grenades you can have a total of 5 of these, meaning no room or defense is any trouble to you. Overall better for killing enemies than defenses.