Cluster GrenadeAttack, AoE, Projectile, Grenade, Fire, Duration Tier: 13 Level: 1Place into a Skill Gem socket to gain this skill. These are found in the Skill Gems panel.
The following support gems are recommendations by GGG as listed in-game, and do not necessarily reflect optimal combinations or the views of the wiki.
Gem tier
Support gems
I
Fast ForwardFast ForwardDuration Tier: 1 Level: 1Supports any skill that has a duration, making that duration shorter.Supported Skills have 30% less Skill Effect DurationPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Fire InfusionFire InfusionAttack, Fire Tier: 1 Level: 1Supports Attacks, causing them to Gain Fire Damage but deal less Cold and Lightning DamageSupported Attacks Gain 25% of Damage as extra Fire Damage Supported Attacks deal 50% less Cold and Lightning DamagePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Magnified EffectMagnified EffectAoE Tier: 1 Level: 1 Cost & Reservation Multiplier: 120%Supports any skill with an area of effect, making it larger.Supported Skills have 40% more area of EffectPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
II
IngenuityIngenuityTier: 2 Level: 1 Cost & Reservation Multiplier: 110%Supports skills with Cooldowns, increasing the rate at which those Cooldowns Recover.Supported Skills have 30% increased cooldown recovery ratePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Primal ArmamentPrimal ArmamentAttack Tier: 2 Level: 1 Cost & Reservation Multiplier: 120%Supports Attacks that use a weapon, causing them to deal more weapon Elemental damage.Supported Skills deal 25% more Weapon Elemental DamagePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Rising TempestRising TempestTier: 2 Level: 1 Cost & Reservation Multiplier: 120%Supports Skills which deal Damage, raising Elemental Damage dealt for each Skill used Recently of a different Elemental type. Cannot support Minion Skills.Supported Skills deal 12% more Elemental Damage for each Skill used Recently of a different Elemental typePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
III
Coming Soon
Elemental FocusElemental FocusTier: 3 Level: 1Supports any skill that Hits enemies, causing it to deal more Elemental Damage but be unable to inflict Elemental Ailments.Supported Skills deal 25% more Elemental Damage Supported Skills cannot inflict Elemental AilmentsPlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
PayloadPayloadGrenade Tier: 3 Level: 1Supports Skills which fire Grenades, giving fired Grenades a chance to activate again, but lengthening their cooldowns.Supported Skills have 70% reduced Cooldown Recovery Rate Grenades fired by Supported Skills have 50% chance to activate a second timePlace into a Skill's Support Gem socket in the Skills Panel to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
Item acquisition
Cluster Grenade has restrictions on where or how it can drop.