This set includes 40 iron spiral corset boning pieces in four sizes: 14.8cm (5.8"), 20cm (7.9"), 35cm (13.9"), and 40cm (15.7"). Each piece has a width of 5.5mm and a thickness of 2mm. Designed with a pre-capped feature, these bonings are easy to use and help improve sewing efficiency. Made from sturdy iron with exquisite craftsmanship, they are durable and suitable for long-term use. The versatile design makes them ideal for creating corsets, wedding dresses, underwear, evening dresses, and more. Please note that due to manual measurement, there may be slight size variations, and color differences may occur depending on screen display. The package contains 40 pieces, with 10 pieces of each size, providing a comprehensive set for various crafting needs.