A Sram Powerlink means you can break a chain without tools. It's easiest to do this on the bike if you have a 'C' shaped wire hook to connect the chain together. It's easy to make one of these from a broken spoke. A Sram Powerlink replaces one outer link of chain. Prepare the chain 1/2 an inch short with an inside link at each end.
Isolate the section of chain with the Powerlink using the ‘C’ hook.
Squeeze the Sram Powerlink
Press the sides of the Sram Powerlink to unclip it. You can do this by hand if the chain is clean. Wash the link with degreaser and rinse with water. If finger-power doesn’t work use a pair of pliers carefully.
Push the links on either side of the Sram Powerlink towards each other so the plates of the Sram Powerlink slide past each other and the pins line up with the bigger part of the ‘keyhole’.
Pull the Powerlink apart sideways to break the chain.