Thurisaz

i'm just guessing here, but i think you measure the pickup's outer most slugs/screw's centers' distance from eachother. you can go right to duncan's main site, pick any humbucker, and click "dimensions" for either standard or trembucking. it says standard spacing for the screws is 2" though btw.

Thurisaz eh? "It may represent an unskilled brutal person." Interesting choice of user name - I keep a drawing of that rune in my car as a protection symbol.