Din 838 - Box Wrenches Double Head Standard Dimensions and Specifications Click the Button to Download Din 838 – Box Wrenches Double Head Standard Dimensions and Specifications in PDF Format DIN 838 PDF Steel: 4.8, 5.8, 8.8, 10.9, 12.9Stainless: A2,A4 Terminology and Measurements d – The Nominal Diameter of the Threadl – Length of Bolts – Size Hex Head Turnkeyb – Length of the Threadk – Head Heighte – The Diameter of the Circumscribed Circle