The specific configuration makes wire forming of the spool. They can be used in almost any form, and springs of this type are usually custom-made and can range in size from very small to very large. The wire can be bent, cut, wrapped around, shaped into a closed coil, and additional parts can be added, as well as anything the customer can think.
Typical materials range from steel and steel alloys to aluminium, brass bronze, stainless steel, etc.
