ST-CCKNIFE. Safety Technology Credit Card Foldable Knife Safety Technology Credit Card Knife has the edge on subtle personal safety! The knife blade is discreetly hidden inside a black credit card with blade-lock. Pop the blade-lock and easily fold into a usable pocket knife! Surgically sharp, quality steel neatly tucked away in your wallet or coat pocket, ready when you need it. The blade is 2 3/4 long when extended. It measures 3 3/8 x 1/8 x 2 1/8 when in the credit card shape. Price: $1.03 Unit: Each Quantity: