PixelSquid PSD content contains layers called Selection Areas to assist in quick and accurate masking of various portions of an object using density selection and color-keying tools such as the Magic Wand. A typical workflow would be to select a Selection Areas layer with layer visibility off, and click the area you wish to select with the Magic Wand tool set to a tolerance of 1.
PixelSquid object > Advanced > Selection Areas > Select by Part: The Select by Part layer assigns a solid color to various parts of the object based on their geometry. Generally, if a part of the object can be considered an object in and of itself (the handle of a hammer, a gear in a watch, etc.) then it will likely have its own color patch on the Select by Part layer.
PixelSquid object > Advanced > Selection Areas > Select by Material: The Select by Material layer assigns a solid color to various parts of the object based on their material. Generally, parts of the object sharing the same material (dark wood, green plastic, etc.) will be assigned the same color on the Select by Material layer.