McGard Propeller Lock Bolts - 851057 Product description:Protect your precious outboard motor with the McGard Propeller Lock Bolts - 851057. This high-quality anti-theft device is designed to secure propellers against theft and vandalism. Features: High security: Made of hardened steel with a unique key code for maximum security. Easy installation: Can be mounted in minutes without special tools. Weatherproof: Designed to withstand extreme weather conditions. Compatibility: Fits most outboard engines with 3/8" (9.5 mm) propeller shaft diameter. Specifications: Model: 851057 Material: Hardened steel Key code: Unique Propeller shaft diameter: 3/8" (9.5 mm) Contents: 2 lock bolts, 2 keys Benefits: Protects your outboard motor from theft Prevents vandalism Easy to install Weatherproof Compatible with most outboard motors