PoE2
Chain
Support
Chaining, Projectile
Requires: Level 1
Support Reqirements: +5 Dex
Supports projectile skills and any other skills that Chain, causing them to chain additional times.
Supported Skills Chain +1 times
Supported Skills Chain 100% more times
Supported Skills deal 50% less Damage with Hits
Place into a Skill's Support Gem socket in the Skills menu to apply its effects to that Skill. You cannot have multiple copies of the same Support Gem socketed at the same time.
PoE1
Chain Support
Support
Chaining, Projectile
Level: (1–20)
Cost & Reservation Multiplier: 150%
Requires: Level (38–70), (63–111) Dex
Supports projectile skills, and any other skills that chain.
Supported Skills Chain +2 times
Supported Skills deal (11–30)% less Damage with Hits

Additional Effects From Quality:
Supported Skills have (0–10)% increased Chaining range
This is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Skill Gem you wish to augment. Right click to remove from a socket.