Durable steel construction with an oxide coating provides rust and corrosion resistance while maintaining a smooth surface for easy use under high compression. Easy to use - Connect the spiral spring compressor until you contact the center rod, then insert the compressor into the valve spring. - Compress the spring for installation or removal, and release the compression only when the spring is set for installation. - The compression spring stores significant energy, so handle carefully and decompress slowly. Tool box storage - Includes 5 adapters of different sizes to fit a range of valve spring diameters and ensure a secure, proper fit for safe compression. - The 10 pieces are neatly packaged and organized in a plastic box for convenient storage and transport. Function and compatibility - Five adapters in different sizes cover various spring diameters on most cylinder heads. - Enables correct valve spring installation and simplifies the use of the compressor. Applications - Automotive engine maintenance and valve spring replacement on most cylinder head configurations. - Engine rebuilds requiring safe removal and installation of valve springs. - Servicing engines with mixed valve spring sizes across different cylinders, facilitating consistent, reliable compression.