Sold as a pack of 6.Olfa PRB18-2 18mm Perforation BladeBlade Specification:Blade Diameter: 18mmBlade Thickness: 0.3mmReplacement Blade For Olfa PRC-2Tungsten SteelPack contains 2 Rotary Perforation Cutter Blades in a plastic case. This blade fits any 18mm Rotary CutterPerforation rotary blades make very convenient perforated lines on paper, cardboard, thin plastic, etc. for easier folding or teari..