I made up a couple of items some time ago, based on those in Baldur's Gate 1/2.
Gauntlets of Weapon Focus: In the hands of a character with at least a +1 Base Attack Bonus, these leather gauntlets provide a +1 bonus to attack rolls, just as if she had the Weapon Focus feat. Both gauntlets must be worn for the magic to be effective. The benefits do not stack with those from the actual Weapon Focus feat.
Caster Level: 4th; Prerequisites: Craft Wondrous Item, Weapon Focus; Market Price: 1,500 gp; Weight: 1 lb.
Gauntlets of Weapon Specialisation: These gauntlets are made of soft leather with metal plates covering the back of the hands and fingers. When worn by a character with at least a +1 Base Attack Bonus, they function exactly like gauntlets of weapon focus. When worn by a fighter of at least 4th level, however, they provide a +1 bonus to attack rolls and a +2 bonus to damage rolls, just as if she had the Weapon Focus and Weapon Specialisation feats (these benefits do not stack with those from the actual Weapon Focus and Weapon Specialisation feats). For ranged weapons, the damage bonus only applies against targets within 30 feet. Both gauntlets must be worn for the magic to be effective.
Caster Level: 7th; Prerequisites: Craft Wondrous Item, Weapon Focus, Weapon Specialisation; Market Price: 6,000 gp; Weight: 1 lb.
(No, this doesn't have anything to do with the actual topic, but I thought I'd mention them anyway.

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