Metamagic rod, Extend, greater
(Dungeon Master's Guide v.3.5, page 236)
Price (Item Level): 24,500 gp (15th)
Body Slot: — (held)
Caster Level: 17th
Aura: Strong; (DC 23) no school
Activation: —
Weight: 5 lb.
You can cast up to three spells per day, of 9th level or lower, whose durations are doubled as though affected by the Extend Spell feat.
Prerequisites: Craft Rod, Extend Spell.
Cost to Create: 12,000 gp (plus 500 gp for base item), 960 XP, 24 days.