Helix Geometry Set Helix from $3.82 $3.59 Qty. Add to Cart SKU: HX17881 This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Includes: bevelled-edge ruler, 12cm protractor and pair of 16cm 45\u730â–‘ and 60\u730â–‘ triangles. Graduations are in inches and centimeters. Tweet