The Flying Dutchman Five Dozen Scroll Saw Blade Variety Pack comes with five different styles of blades to try and compare. Included is one dozen of each: UR5, SR5, PS5, P5, and NS3 blades. -UR5 (Ultra Reverse #5) is our top selling all around scroll saw blade. Aggressive with a smooth cut. -SR5 (Scroll Reverse #5) is a skip tooth blade with reverse teeth for less cleanup. PS5 (Penguin Silver #5) is a good blade for thicker materials. P5 (Polar #5) is a regular skip tooth blade, good for wood, bone, Corian, acrylic, and more. NS3 (New Spiral #3) is a great spiral blade wih a smoother cut edge than a regular spiral. Flying Dutchman scroll saw blades are 5" long and are pinless. They are all milled blades, which makes for a sharper cutting edge. Flying Dutchman blades are manufactured in Germany with top-grade, high-quality hardened steel.