If I have equipment that gives +2 Might, how much Might does Gearhead get when Svellsongur is also in play?

Ruling: Gearhead with Svellsongur attached gives +4 Might from a +2 Might equipment. The second instance of "double its base might bonus" from Svellsongur does not stack with Gearhead's existing ability.

Sequence:

• Gearhead's ability makes equipment give double its base Might bonus (+2 becomes +4)
• Svellsongur adds a second identical ability to Gearhead
• Both abilities reference "base might bonus" (which is still +2)
• Since both abilities set the same value (double of +2 = +4), they don't stack
• Final result: +4 Might

Nuances:

• The key word is "base" - both doubling effects look at the original +2 value, not at each other's results
• The ability uses "gives" not "doubles", which affects how the effects layer
• This makes Svellsongur redundant when attached to Gearhead