Review on 4 Pairs Re-Usable Quick Link For Bike Chains - Compatible With Shimano/KMC/Campagnolo/SRAM | Inkesky by Edwin Kreps

This is a link that can be used to re-attach a broken chain or connect a new chain. It should not be re-used. It also should be installed rotationally correct. These can be installed by hand and though it is a little harder removed by hand. My suggestion is to purchase a removable link tool which makes installation and removal easy. In my opinion the 12 speed chain is vulnerable and keeping one of these links along with a tool in your bike bag is cheap insurance.