Galvanized Carbon Steel: Our tension spring is made of carbon steel, with the surface zinc plated to prevent oxidation and corrosion. The high-quality springs have good fatigue resistance and high ductility, ensure evenly stressed and long service life. Package Includes: Springs assortment set includes 200 pieces of small spring in total. Compression springs in 8 sizes, from 5.5mm to 9.5mm, 76 Pcs in total. Extension springs in 12 sizes, from 4.0mm to 8.5mm, 124 Pcs in total. With Storage Boxed: Comes with a plastic box with compartments for separate storing these springs of different sizes. There is a size and picture comparison table on the box lid for reference. You can always quickly pick out the exact size you need. Wide Applications: These compression springs and extension springs kit can be used to repair and replace springs of various items. Ideal for toys, motorcycles, equipment, battery box, bicycles, locks, switches, appliance, tools, auto, woodworking, mechanical and more. Specifications: EXTENDED SPRINGS: 5x20.5mm, 10Pcs./ 8.5x36.5mm, 10Pcs./ 5.5x25.5mm 10Pcs./ 8x28.5mm, 8Pcs./ 6.5x22mm, 10Pcs./ 8x31.5mm, 10Pcs./ 8.5x47mm, 12Pcs./ 8x44.5mm, 12Pcs./ 7x51mm, 12Pcs./ 4x79.5mm, 12Pcs./ 7x38mm, 12Pcs./ 4.5x44.5mm, 8Pcs. COMPRESSED SPRINGS: 7x12.5mm, 10Pcs./ 9.5x16mm, 6Pcs./ 6.5x10mm, 10Pcs./ 9.5x16mm, 12Pcs./ 7x19mm, 10Pcs./ 9x35mm, 8Pcs./ 5.5x38mm, 10Pcs./ 9.5x17mm, 10Pcs.