The Park Tool MLP-1.2 Master Link Pliers are used to either disengage / separate / remove the chain master link, or to join the master link during chain replacement.
The SRAM PC-951 9-Speed chain used on my bicycle has a master link, a set of two identical plates, each with an identical pin. To assemble, a plate / pin assembly is pushed into the end hole on each side of the chain. The Pin is fit into the keyhole opening on the opposite plate, then the chain is pulled to catch the pin into the keyhole.
The tool usage is EASY. Grab onto the master link and squeeze the handle.
The tool has a nice cushion grip.
The MLP-1.2 measures 6.5" long, 2.18" wide (handle squeezed), 0.12" thick (each steel plate) and 0.66" thick (cushioned grip). The mass is 146g.
I would not hesitate to recommend this tool.
