Measuring 4.5 inches closed, this Ball Bearing Pivot Folding Knife from MTech USA features the A.C.S. lock which uses a spring loaded plunger to hold the knife open essentially locking the blade into place. Depressing the button lines up a notch in the plunger and allows the blade to pivot on the ball bearing system. The A.C.S. lock is a strong lock that doesnt require the user to put a finger in the blades path when closing the knife. The lock is both fast, safe and easy to use. This knife has a 3.1 inch satin finish stainless steel blade and an orange aluminum handle and comes complete with a pocket clip for easy and safe carry.