Ring of Yoba

Occasionally shields the wearer from damage.
Overview
The Ring of Yoba is a craftable ring unlocked after reaching Combat Level 7. Its recipe requires 5 Iron Bars, 5 Gold Bars, and 1 
Yoba’s Blessing grants immunity to monster damage for 5 seconds. It does not prevent damage from falling down Skull Cavern shafts. The ring’s activation chance increases when the player is at low health and is also boosted by Luck buffs, but not by daily Luck. It can begin activating once health drops below 90, then rises linearly until 15 health, where an additional 20% bonus applies. For a player with 0 Luck and 100 maximum health, this works out to a 25% to 0% activation chance between 16 and 90 health, and a 50% to 45% chance between 0 and 15 health.
Equipping a second Ring of Yoba gives no extra benefit. The ring can also be used in dyeing, where it serves as a yellow dye at the dye pots in 

Official description
Occasionally shields the wearer from damage.