HIPLOK uses a four tier security rating system featuring Basic Medium High and Maximum levels. Maximum security D lock noose style chain and security tie combine for maximum potential. 14mm hardened steel shackle with 10mm hardened steel chain. Perfect for E bikes cargo bikes and other non standard frames . Rated Gold by Sold Secure`s independent lab testing. 3 coded replacement keys. D lock is 3.35` x 5.90`