Zinc blade slider for durability and strength No tools needed to change utility blade – quick and easy to replace blades Interlock mechanism allows only one blade to be extended at any one time - for safety Thumb slider - for easy operation of a utility blade Positive spine lock fixes blade when opened - for safe operation Separate traditional utility blade ideal for professional heavy-duty cutting 3” / 75mm serrated blade for a garden, hobby, and outdoor use Comes with holster and blades for better value