Slip Knot 133 Mask This Slipknot costume mask includes one 133 black overhead latex mask with spikes. Become The Silent One in this classic style 133 latex Slipknot costume mask. This classic style Slipknot 133 Mask is an officially licensed Slipknot costume accessory. This 133 Mask is an officially licensed Slipknot costume accessory. This what true fans of the popular band SlipKnot wear to show how far they&#039;re willing to go.