Brass compression fittings form leak-free copper pipe connections without needing a torch.
Brass compression fittings have a ferrule and compression nut at every plumbing pipe connection.
The compression nut squeezes the ferrule, a brass ring, against the plumbing pipe and the compression fittings brass body.
The pressure applied to the ferrule by the compression nut seals the connection.
Unscrewing the compression nut will disconnect the compression fitting from the plumbing pipe; the ferrule and compression nut remain on the pipe.