Alternating links of a strange green metal and ivory make up this chainlike belt.

A desperation chain gives an arcane spellcaster the opportunity to either avoid capture or strike back against an enemy.
You can activate a desperation chain when you are being rendered helpless by an enemy (such as being pinned, paralyzed, or dropped to –1 or fewer hit points). When you activate the chain, you can cast a single arcane spell of 3rd level or lower without spending an additional action to do so.
Doing this expends the prepared spell or spell slot as if you had cast the spell. The chosen spell must have a casting time no longer than 1 full round. Casting a spell in this way requires no verbal or somatic components and does not provoke attacks of opportunity. You must still provide any material components or focus required, as well as pay any XP or other costs of the spell.
The spell you cast takes effect after the effect that rendered you helpless (so it can’t prevent that effect), though it could theoretically neutralize or reverse it. For example, a bard wearing the chain could cast cure light wounds in response to being reduced to –3 hit points.
This ability functions once per day.
You must wear a desperation chain for 24 hours before you can access its abilities. If it is taken off, it becomes inactive until worn for an additional 24 hours.

Prerequisites: Craft Wondrous Item, limited wish.
Cost to Create: 7,500 gp, 600 XP, 15 days.