OnGuard makes the meanest, toughest locks in the business.

On the inside, OnGuard locks earn the highest safety ratings with double and quad-locking mechanisms, bump-resistant cylinders, and hardened steel shackles and chains. On the outside, our locks are fully-coated to protect your bicycle or powersport vehicle from scratches and to shield internal parts from the elements, while the bright color scheme sends a clear warning to thieves: don’t even try! And then there’s the extras: all-tube mounting brackets, five laser cut keys, key-code registration, comprehensive anti-theft programs, limited lifetime warranties and the best sales and customer support team in the business.

Bull Mastiff (8103)

• 10mm hardened steel shackle

• Rotary style lock provides smooth, one-handed operation

• Tick shackle-to-body clearance eliminates pry points

• 5 heavy-duty F-style keys