Used to make Tee connections where tight areas don’t allow an 8 inch or greater radius or to run in opposite directions. You can run 4 cables through these in a tic-tac-toe fashion. Useful for many designs of installation. Available in aluminum and bronze.
Bolt tension connecters are the best. You tighten it well enough and you never have to worry if it will come loose, especially in concealed systems. It’s well worth the extra money. It’s all we use on our installations.