Dual bolt locking mechanism with Dual Lockdown Protection drives 2 hardened pins into the 13mm ultra hardened steel shackle at both ends creating a double lock that can withstand 6 tons of pull forceImproved M-Cylinder lock mechanismRotating dust cover protects cylinderProtective vinyl coating on shackleDouble rubber coating on crossbar13mm U-lock 3.5″ x 5.5″ with 10mm 4ft. cable