Armored Avatar Piercers are an epic-quality equipment item that are only available to Villains and are sold by Requisitions-T2V. Once equipped, they unlock the Avatar Bombardier hands costume style.
Source
The Armored Avatar Piercers are sold by Requisitions-T2V, a vendor found within the Power Core of the Hall of Doom. The item costs $343 and 50x Mark of Conquest.
Vendor item
Style unlock
Upon equipping the Armored Avatar Piercers, a character unlocks the Avatar Bombardier hands costume style, which can be accessed at any time from the Style Window.