Stahlex Superlock U-Lock This Stahlex Superlock is in safety category B, making it extra strong. The categories range from the letter H to A, with the letter A being the highest safety category. Specifications: Total length: 330 mm Shackle thickness: 18 mm Total width: 167 mm Weight: 2180 grams Shackle material: heavy hardened steel Holder material: impact-resistant plastic Safety category: B Color: black Contents: 1 Stahlex Superlock 1 Lock holder 2 Keys