It is the universal computerized lettering blade, suitable for Explore Air 2/Air/Maker/Expression, it has 3 sizes, different degrees of replacement blades to meet your needs for different crafts. The blades are made of tungsten steel, which is characterized by high hardness, abrasion resistance, strength and toughness,will make your handiwork smoother better. 45 Five Point Blades - These Blades are capable of making most general purpose cuts on medium-weight materials such as glitter paper, foiled card stock, adhesive foil, poster board, and computer paper, vinyl, stickers. 60 Deep Point Cut Blades - specially designed for making most intricate and delicate cuts on thin materials such as magnet, chipboard, stamp material, thick card stock, foam sheets, cardboard, and some fabrics. 30 Shallow Cut Blades - recommended for thin material such as window tint, film, rice paper and bonded fabric. Specification: Material: Tungsten steel Full length: 23.5mm/0.93inch Blade handle diameter: 2mm Package Includes: 1 Piece Blade Holder 15 Pieces Cutting Blades