One best feature of the credit card knife is the safety it offers to users. Although the knife is razor-sharp and has a long blade, it cannot be tampered with once it is safely locked. Yes the credit card knife comes with a lock and sheath that once it is closed, it is very safe to carry even in your pocket. The sheath also prevents the blade from blunting which could affect the performance of the blade. Once the blade is in cutting mode, it is quite tight and secured avoiding blade tremor which is common in pocket knives. This affects the performance of the blade and could even lead to accidents.