You can purchase here, from this site, or you can find Cloak of Protection at these stores:
AUCKLAND
Tiritiri Matangi Island
Waiheke Community Art Gallery, Oneroa
HAWKES BAY
Tauranga Art Gallery, Toi Tauranga
TAUPO
Taupo Museum
KAPITI COAST
Mahara Gallery, Waikanae
Nga Manu Nature Reserve, Waikanae
PORIRUA
Toi Store, Pataka Art + Museum
WELLINGTON
Expressions Arts & Entertainment Centre, Upper Hutt
Zealandia: The Karori Sanctuary Experience (also, Flight of Pollen)
Aratoi: Wairarapa Museum of Art and History
SOUTHLAND, FIORDLAND, STEWART ISLAND
Rakiura National Park Visitor Centre, Stewart Island
Fiordland National Park Visitor Centre, Te Anau