Stable construction: two top layers of longitudinally oriented glass fibres absorb bending forces + provide higher stiffness than wooden metres. No swelling on contact with water, resistant to chemicals. Joint: Backlash-free, wear-free and dirt-resistant joint of the folding rule with spring rod for uniformly high tension. Tight 90 ° and 180 ° detent of all joints. Accuracy of the folding rule: CE conformity, EU standard accuracy class II. Captive metal ends on start and end links. Reading on both sides by backward running scale (recto verso). Graduation: Version red/black: Deep embossed white graduation in 1 mm steps, white embossed tens Extra: Reading on both sides by backward running scale (recto verso). Extra: Captive metal ends at beginning and end link. Joint: Backlash-free, wear-free and dirt-resistant joint with spring rod for uniformly high tension. Tight 90° and 180° locking of all joints. Accuracy: CE conformity, EU standard accuracy class II. Material: Composite construction: two cover layers of longitudinally oriented glass fibres absorb bending forces and thus provide greater rigidity than wooden metres. Material: No swelling on contact with water, resistant to chemicals. For applications in mechanics