Helix Clear Plastic T-Square Product Code: Helix Clear Plastic T-Square $6.99 to $11.99 AS - Size - Rulers/T-Squares : 12" 18" Qty: -+ Add to Cart The Duck Store RewardsEligible for 6.99 pointsLearn moreOverviewMade of clear, blue-tinted, flexible plastic, these T-squares have both standard and metric scales.