Well, this is not so much a custom item than it is an item from the Magic Item Compendium in 3.5. Here it is:
ARMBANDS OF MIGHT
Aura Moderate Transmutation; CL 6th
Slot Wrists; Price 10,500 gp; Weight 1 lb.
DESCRIPTION
These bronze armbands are engraved with images of bulls' horns.
The bearer gains a +2 Competence bonus on Strength checks and Strength-based skill checks. If the bearer has the Power Attack feat, he treats his base attack bonus as 4 higher for the purposes of calculating his bonuses from the Power Attack feat. Both armbands must be worn for the magic to be effective.
CONSTRUCTION REQUIREMENTS
Craft Wondrous Item, bull's strength; Cost 5,250 gp