SAVING THROWS AGAINST MAGIC ITEM POWERS
Magic items produce spells or spell-like effects. For a saving throw
against a spell or spell-like effect from a magic item, the DC is 10 + the level of the spell or effect + the ability
modifier of the minimum ability score needed to cast that level of spell.
Most item descriptions give saving throw
DCs for various effects, particularly when the effect has no exact spell equivalent (making its level otherwise difficult to determine quickly).