The R5X GHOST - Skull Knuckle is a special Helmet in Blacklight: Retribution that is based on the Allied R5X GHOST and has the same stats.
This is a variant of the Allied R5X GHOST and shares its stats.
This helmet could previously only be won through the "RARE HELMET LOTTERY BOX", which was available post-Parity Patch, until it was removed in the Holiday Update on the 18th of December, 2015.
It is currently not for sale in the Customization Menu.
In-game Description Edit
Light helmet. A skull adorns this version of the Allied R5X GHOST.