Wallboard Tool 09-001 0.18 x 47.87 in. Drywall T-Square The ORIGINAL Drywall T-Square. Heat treated aluminum construction. 3/16" blade thickness. 47-7/8" blade length. Cross-head is angled for added strength. Aircraft alloy steel rivets attach head to blade. Reverse ruled blade for precise measurements in either direction. Head is calibrated to make accurate 16" (406mm) stud. Clear anodized finish.