Koolaburra Crystallized Tribal Heart an authentic Australian Ugg boot features sheepskin upper, replaceable sheepskin insoles, form fitting foam footbeds, comfortable EVA soles, and a tribal heart tatu design in colorful Swarovski crystals on the shaft. Crystallized Tribal Heart is available in black or chestnut. Koolaburra Crystallized Tribal Heart is a comfortable authentic Australian Merino sheepskin boot that will keep your feet warm and stylish with the unique crystallized tattoo design.