These blades are designed for cutting wood, plastic and thin non-ferrous metals (copper, zinc, brass, lead and aluminum). These saw blades fit the replacement for Dremel Moto-Saw MS20 or MS20-01 2 in 1, which uses pinged saw blades with a total length of 4.13 inches (105 mm) and a distance of 3.94 inches (100 mm) between the pins. Please note that these saw blades do not fit the old replacement for Dremel Moto-Saw that uses 3 inch saw blades. The fine blades (similar replacement for Dremel MS53-01) have 24 normal teeth per inch, 0.010 inch thickness and 0.074 inch width for particularly smooth cuts, particularly sharp curves and for fine work. The middle blades (similar replacement for Dremel MS52-01) have 18 normal teeth per inch, .010 inch thickness and .074 inch width for smooth end cuts and sharp curves. The coarse saw blades (similar replacement for Dremel MS51-01) have 15 normal teeth per inch, 0.018 inch thickness and 0.094 inch width for fast, even cutting and FOXBC 4-inch pin end scroll saw blade replacement for Dremel Moto-Saw with medium turn MS20 MS20-01 MS20-01 MS. 51-01 5MS52-01 MS53-01 48pcs