The Westalee Design 6 Point CROSSHAIR RULER is for marking 3 (120°) or 6 (60°) or 12 (30°) or 24 (15°) reference lines, great for Hexagon Quilt patterns.
The 12.5″ size allows you to mark up to 12″ blocks. AND the 8.5″ size allows you to mark up to 8″ blocks.