Slice 10558 Smart-Retract Safety Box Cutter, Blade Automatically Retracts as Cutting Motion Finishes, Utility Knife with Finger Friendly Ceramic Blade, Blue Smart-Retract technology = Relf-Retracts for safety even if your finger is still on the slider button (Blade Retracts Before End of Cutting Motion to Help Prevent Injury) Easy, No-Tool Blade Change = Less Blade Changes = Less Money = Less Downtime = Less Injuries Stays sharp up to 11x longer than steel + single ceramic blade Equivalent up to 20 single sided metal blades Ergo-pull side slider button + durable gfn (glass filled nylon) handle Ceramic blades never rust, they are non-conductive, non-magnetic, non-sparking , chemically inert and have an oil-free finish (perfect for clean rooms)