A viable perpetuation alternative to Caller's Doublet +2, and provides better DoT during Perpetuation. So with enough perpetuation gear (includes ToM staves/Nirvana), will beat out Caller's +2. However, switch to Caller's +2 for Blood Pacts (still use this when triggering the BP)
it's obtained from trial of magician. trading forgotten hopes (30 to 50 - depending on the relic you have, so 30 to +1 relic or 50 for NQ relic). This armos is useful for SMN who doesn't have Trial of magician staves to get -bp delay. also seems nice to have a +crit, but callers still better for soul syphon, and blood pact ward duration, since it adds +10 smn magic.