Veritas Square Saddle
Transferring a line from one surface to another perpendicular surface with a small square is never easy. Veritas' saddle square solves this problem by allowing you to scribe two perpendicular surfaces at a time. More important, it allows you to pick up on a line already scribed, and accurately transfer it to another face perpendicular to it.
With 1-1/4" x 2-1/4" inside legs, it can be used to wrap a line around workpieces up to almost double this. Made of anodized aluminum, 2" wide, with both end faces machined square to within 1/4°.