Bike Chain Lock ONGUARD MASTIFF 8120 120 cm × 8 mm with 5 coded keys

ONGUARD MASTIFF 8120 is a bicycle chain lock with a 120 cm long, 8 mm thick chain designed for securing bicycles and comparable outdoor equipment. The set includes five coded keys to simplify day-to-day access and to provide spare keys for replacement. The chain format allows flexible fastening around frames, poles and bike racks, making it suitable for urban and commuter use where a combination of reach and moderate resistance is required.

Advantages

The MASTIFF 8120 combines a long, articulated chain with a compact coded locking mechanism to deliver versatile security without excessive bulk. An 8 mm steel chain offers a balance between flexibility and cut resistance for routine outdoor locking. Including five coded keys reduces the risk of being locked out and makes it easier to share access with family members or caretakers. The chain coating protects the bicycle finish while providing weather resistance for everyday use.

Suitable for

• Securing adult and children's bicycles in urban environments
• Locking bikes to racks, poles or fixed structures
• Short- to medium-term locking during commutes, errands or school runs
• Use with scooters, wheelchairs or other outdoor equipment of similar size

Key specifications

• Chain length: 120 cm
• Chain thickness: 8 mm
• Lock type: coded key lock with five supplied keys
• Chain format: articulated links with protective coating
• Primary use: outdoor bicycle security

How to use

Wrap the chain around the bicycle frame and a fixed object such as a bike rack or pole, ensuring it passes through the frame and, if possible, the wheel. Insert the chain end into the locking mechanism and turn the coded key to lock; keep spare keys in a secure location. When unlocking, insert the matching key and rotate to release the chain. Store the lock in a dry place when not in use to prolong life and check the coating and key mechanism periodically for wear or corrosion.

Usage recommendations

For the best practical security, lock the frame and at least one wheel to an immovable object, avoid leaving the bike unattended in high-risk locations for extended periods, and carry a spare coded key separate from the primary key. Regularly inspect the chain coating and moving parts; replace the lock if links show significant deformation or the key mechanism becomes stiff.