Cold shuts are a very old-fashioned way of repairing low-grade chains. Once installed, they are a semi-permanent solution--removing one means cutting it out with a saw. They are more difficult to install than more modern types of chain couplers. They need to be bent into position, usually requiring a vise, then peened with a hammer. Having said that, installation is not all that difficult and takes only a few minutes. They feature a zinc plating for protection against corrosion.
NOT RECOMMENDED FOR fall arrest, overhead lifting or other critical applications. No matter how you use these links, always adhere to the Working Load Limits and inspect often.