The watchful Eye of the Uncaring One stares out from this seal.

When affixed to a wizard’s spellbook, this seal provides a focus for arcane energy. A tomebound eye of Boccob has 3 charges, which are renewed each day at dawn.
Spending 1 or more charges when you prepare your wizard spells from a spellbook to which a tomebound eye is attached grants one or more spells a competence bonus on caster level checks to overcome a target’s spell resistance.
1 charge: Gain a +4 competence bonus on your caster level check to overcome spell resistance.
2 charges: Gain a +6 competence bonus on your caster level check to overcome spell resistance.
3 charges: Gain a +8 competence bonus on your caster level check to overcome spell resistance.
You can divide the 3 charges between spells, or spend all three to enhance a single spell. For example, you could grant three spells each a +4 bonus, one spell a +6 bonus and another a +4 bonus, or a single spell a +8 bonus. No spellbook can have more than one of these items affixed to it, and you can’t gain benefits from more than one eye in a given day.

Prerequisites: Craft Wondrous Item, ability to prepare 3rd-level arcane spells.
Cost to Create: 3,500 gp, 280 XP, 7 days.