This 10 pack of heavy-duty replacement blades is compatible with all Spec Ops Safety Knives. Refill any safety box cutter with the sharp, high carbon steel construction of these blades. Featuring a patented radius tip that helps to prevent injury and product damage, these sharp edges safely and effectively cut through cardboard cleanly and easily every time. These replacement blades are designed to cut up to 5,000 feet while lasting 3x longer than the industry standard. We support our nation's heroes by donating 3% of proceeds to veteran and first responder causes.This 10 pack of heavy-duty replacement blades is compatible with all Spec Ops Safety Knives. Refill any safety box cutter with the sharp, high carbon steel construction of these blades