The game's collection data lists Puncture-Proof Greathelm as sold by a vendor NPC in Stormshield.
Vendor
Zone
Map
Waypoint
Other items it sells
NPC #93914
Stormshield
-
-
169
Vendor NPC, zone and position come from the client's collection source tables (CollectableSourceInfo and CollectableSourceVendorSparse); coordinates are the in-game map readout.
Build history
First seen in build 5.5.4.69585 (Mists of Pandaria).
Read from the World of Warcraft client build files.
How Puncture-Proof Greathelm Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Puncture-Proof Greathelm suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Puncture-Proof Greathelm is part of the transmog set Battleplate of the Last Mogu (Warrior only). The other 16 pieces:
4 other items in the current build are also called Puncture-Proof Greathelm. Same-name entries are usually a different rank, faction, quest stage or reward track of the same object.
Blizzard numbers items as they are created, so the named items next to ID 96024 (96019 to 96029) were usually added in the same batch as Puncture-Proof Greathelm: the same quest line, zone, vendor or reward set.