Dual .50 Caliber Pistols
From WikiRaider
Dual .50 Caliber Pistols (also Dual 50 Caliber Pistols, without the dot) are introduced in Tomb Raider Anniversary and replace the Magnums from Tomb Raider.
They are more powerful than the normal Dual Pistols and Mini SMGs Lara uses. You can find them in the Colosseum.
Official Description
A pair of high caliber pistols. A slightly slower rate of fire than normal pistols is offset by increased damage.
Tomb Raider Anniversary booklet, page 20