OnGuard | Bull Mastiff Round Key Padlock

Compact size. Serious security.

Designed for users who need dependable heavy-duty protection in a compact form, the OnGuard Bull Mastiff Round Key Padlock combines hardened security features with fast, practical operation for everyday and professional use.

The Bull Mastiff 8103 is built around a 10 mm hardened steel shackle engineered to resist cutting, sawing, and prying attempts. Its precision rotary locking mechanism allows quick one-hand twist-to-lock operation for convenient daily use, while the tight shackle clearance helps minimize leverage points against tampering attacks. Finished with a weather-resistant metal housing, the padlock is built to handle demanding indoor and outdoor conditions alike. Supplied with five heavy-duty F-style keys, it delivers long-term reliability for gates, chains, lockers, sheds, and equipment security.

Key Features

• Heavy-Duty Hardened Shackle
10 mm hardened steel shackle provides strong resistance against cutting, sawing, and prying attempts.

• Rotary Lock Mechanism
Twist-to-lock rotary operation allows fast and convenient one-hand locking.

• Anti-Pry Construction
Tight shackle clearance helps deter leverage attacks and tampering attempts.

• Weather-Resistant Durability
Durable metal housing is designed to withstand outdoor exposure and harsh environments.

Technical Specifications

• Category
Padlock

• Discipline
Lifestyle

• Construction / Material
Metal Housing, Hardened Steel Shackle

• Shackle Diameter
10 mm (0.39")

• Included Accessories
5 F-Style Keys

Suitable for securing gates, chains, lockers, sheds, storage units, and heavy equipment.