Master Lock® Aluminum Padlocks Corrosion-resistant, lightweight, strong, and secure High-Visibility Aluminum Padlocks feature hardened steel shackles, high security 5-pin Pro Series™ cylinders and dual ball-bearing lock mechanisms, available in six vibrant colors. The powder-coat finish resists scratches and UV deterioration and remains bright, even in corrosive and tough environments. Rekeyable design allows 10,000 key changes. Master key and keyed alike configurations as well as 19⁄16" and 3" high shackle options are available. Locks measure 19⁄16" wide by 3⁄4" thick body with a 1⁄4" diameter shackle.