When worn, the Skull Mask provides 2 armour points, or 1 armour icon, and absorbs 8% of damage from the player at the expense of durability. It has a unique overlay over the player's first-person vision when worn, similar to the effect of wearing a Pumpkin. Wights will not be able to use their 'possession' attack on any player that is wearing the mask, making them easier to deal with.
Like most other equipment with durability, a damaged Skull Mask can be repaired to full durability through an Animator. The more that needs to be repaired, the greater the cost of fuel and crystal charge is in the animation process.
As with most equipment, the Skull Mask can be equipped with Middle Gems as part of the Middle Gem Circle to apply additional buffs to the player using it. The type of gem equipped can be seen in its tooltip. The bonuses provided can be seen on the gem's own tooltip.