The OnGuard Mastiff 4.9 ft Chain Lock delivers heavy-duty protection for bicycles, e-bikes, scooters, and outdoor equipment. The 150 cm (4.92 ft) chain features titanium-reinforced hardened-steel square links engineered to resist cutting, twisting, and leverage attacks in urban environments. Its integrated lock head uses OnGuard’s X2P Dual Lock Down mechanism, securing both sides of the shackle to improve resistance against pulling and prying attempts. A durable double rubber-coated lock body helps absorb impacts and protect finishes, while the protective sleeve helps prevent scratches and shields the chain from corrosion and weather exposure. An automatic keyway cover helps block dust and moisture from entering the lock cylinder for reliable long-term performance. Includes five precision laser-cut keys.

• X2P Dual Lock Security: Integrated lock head secures both sides of the shackle to resist pulling, twisting, and prying attacks.
• Titanium-Reinforced Chain Strength: 150 cm (4.92 ft) hardened-steel square-link chain engineered for strong resistance to cutting and leverage attempts.
• Extended Heavy-Duty Coverage: Longer chain length allows flexible locking to racks, poles, or fixed structures for bikes and e-bikes.
• Protective Weather-Resistant Sleeve: Durable cover helps prevent scratches and protects the chain from corrosion and outdoor wear.
• Complete Key Set Included: Comes with five precision laser-cut keys.


Manufacturer Sku: 8121
Todson Sku: 45008121