... ,Nickel,Silver,Golden,Tin-plated,Powder coating Usage Generally used in telecommunication, medical instruments, optical equipments , power supply, switch, ... be sent before shipmentDelivery PortXiamen,ChinaAdvantage1.Many years experience in manufacturing spring2.Experienced engineers and technicians,Skilled Workers 3. ... chain spring/strong forged steel link chain for slings binding (SGS certificate)