# Ring of sustain ability

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Name

sustain ability

Appearance

random

Base price

100 zm

Weight

3

Probability out of rings

3.57%

Probability out of items in:

containers

Rogue level

Gehennom

Elsewhere

0.179%

0.179%

0.286%

0.107%

The ring of sustain ability is a ring that appears in NetHack. 
When worn, it prevents the wearer's base attributes from being changed in any way, except by polymorphing into your own race. This includes stat increase through exercise, as well as stat loss from abuse.

Strategy
The ring is quite beneficial in short-term scenarios; for instance, if you lack poison resistance but have identified the ring early, it is useful to wear while eating poisonous corpses—this avoids the usual strength loss, and the ring can safely be removed after you have the resistance. As a more general use, it is employed to prevent stat loss from any sustained abuse, usually resulting from deliberate actions (e.g. constant satiation combined with a ring of slow digestion to save food).
The ring can also be used to prevent the intelligence drain from a mind flayer's attack, but it does not directly protect against death by brainlessness; if your intelligence is already 3 when you put the ring on, then one successful brain-eating attack will still put an end to your game. The ring also does not stop the attack's amnesia effects.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

mind flayers can no longer inflect amnesia, thus making the ring an effective mitigation against the mind flayers's worst attacks. 
Identification
In addition to identifying it via sink or wand of enlightenment, a player can identify a suspected ring by wearing it and doing something that would alter their attributes, e.g. eating a tin of spinach, quaffing a non-cursed potion of gain ability, sitting on a coaligned altar, or applying a cursed unicorn horn.

History
Before NetHack 3.6.1, a bug allowed you to use a ring of sustain ability to increase strength. When wearing the ring, if your nutrition status changes to Weak, your strength wouldn't go down as it usually does. However, if you then removed the ring and then raised your nutrition status to Hungry, your strength would increase as usual.
This could be farmed or abused to raise your strength to its racial maximum, provided that you have a large number of low-nutrition comestibles (such as meatballs). You first get your nutrition status to Hungry, and then:

Put on the ring of sustain ability;
Wait until your hunger status changes to Weak;
Remove the ring of sustain ability;
Eat a meatball (or enough meatballs to go from Weak to Hungry);
Repeat steps 1 through 4 until your strength reaches its racial maximum.
A ring of hunger, conflict, or regeneration will speed up this process. Beware of possible negative effects, especially if the ring is cursed.
This would be especially productive for characters who start with low strength and the stone to flesh spell, such as Healers.

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.6.1. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-361}} tag to the current version's tag or {{noversion}} as appropriate.