If released, it would have come packaged with the Nitron.
It is a shield that can block dart fire, which provides adequate coverage. It can attach to any Nerf blaster via tactical rail.
The shield, like the Hydro Cannon shield and Lightningstorm shield, is made of transparent orange plastic. It also appears that the Centerfire Tech electronic scope from the previous release of the Nitron would be probably replaced by this attachment, if the Nitron shield had come out.
The packaging of the first batch of Pyragons showed the Nitron with the shield and an additonal ten disc magazine. It was thought that the Nitron would be updated and given the shield instead of its scope. However, a later update to the packaging had the image replaced with one of a standard Nitron with a scope and single magazine. The shield was never released.