The Delta 40-620 is a 36 Assorted Scroll Saw Blades. It includes 12 each of three popular styles. The 40-605 blades have 27 TPI and are .010 inch thick for very intricate work. The 40-608 blades have 11.5 TPI and are .016 inch thick for less intricate work in thin woods. The 40-616 blades have 9.5 TPI and are .024 inch thick for cutting materials up to 2 inch thick. All of the blades are five inches long with plain ends and fit all Delta scroll saws and others requiring a five-inch plain end blade. Includes 12 of each models 40-605, 40-608 and 40-616.