The small portable skilling pack is a Treasure Hunter reward that contains a portable skilling station. Portables can be withdrawn from packs one at a time, or all small packs in the inventory at once by selecting the 'take all' checkbox. Once the portable is selected, the pack is destroyed.
Small portable packs automatically replaced all portable forges when the Mining and Smithing rework was released, as those were discontinued by the rework and replaced by luminite injectors. Rather than a direct replacement of forge to injector, this item allows the player to choose whether to get the new Smithing 'portable', or get a different portable.
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