Bloc Loc’s Half-Square Triangle Set #5 contains 4 1/2″, 5 1/2″ & 6 1/2″ rulers that lock onto the seam for instant ruler placement, control so that the seam ends in each corner and trims 90% faster than a flat ruler. Ruler rock is gone, too! Also trims quarter-square triangles, birds in the air, y-blocks, LeMoyne Star, double windmill, hidden square units and much, much more. HST rulers are multi-sized and trim in 1/8″ increments. | Contains 3 Rulers: 4.5", 5.5", and 6.5"