Gnomish Cloaking Device Schematic

Zan Shivsproket sells the Gnomish Cloaking Device in the mountains north of Tarren Mill in Hillsbrad Foothills. He is located in the basement of a hidden rogue stronghold in the mountains but the path up there is relatively easy to find. You can buy the Gnomish Cloaking Device schematic for 24 silver and sell it for a few pieces of gold.