1High Strength Material: The spring kit is made of zinc plated steel, which is rust resistant, has maximum strength, and has a long service life, providing additional durability for appropriate tension. 220 Kinds Springs: The spring assortment set includes 200 PCS and 20 spring styles. This cotter pin assortment includes 8 sizes of compression springs and 12 sizes of extension springs, which can meet your different needs. 3Multipurpose: You can choose from 200 different sizes of spring units to meet most of your life and work needs, such as car repairs, home repairs, DIY projects, etc. 4Direct Replacement: The compression and extension springs kit is easy to install and disassemble. Rusted or missing springs can be quickly replaced with these sturdy steel springs for easy use. 5Portable: The convenient transparent storage box holds all the springs together, making it easy to carry, organize. With size markings, which means you can easily find the required springs.