No need for replacement parts: the plunger pin is set captive for life. These exceptionally strong snap shackles are hot drop forged from high resistant stainless steel. Only forging creates a superior steel product, by increasing its elasticity and maximizing the steel's internal strength. A forged snap shackle will deform long before breaking. It will not burst or break suddenly. This is big safety advantage. Built-in thimble disperses load on line.