Springs are the heart of spining cans.It is made of high carbon spring steel wire manufacctured by a renowned steel company with ISO 9002 certification.They are heart treated to ensure fatigue-free performance,uniform collapsibility and release; these are the quality springs of spincan for fitment in nodern spinning machins. Plastic bottom covers are so designed that they allow clustering of coils of the spring within themselves. This allows additional capacity for the silver to fill in.