The Double Uni Knot if perfect for joining two separate segments of line together, especially if they are of different diameter.  This knot is strong and relatively easy to tie.

Make sure you always wet your knots with saliva or Chapstick to make sure they form properly as well as ensuring that they cinch down nice and tight.

The Uni Knot is a strong and easily tied knot that can be used for braided fishing line or monofilament.

The major advantage of the Uni Knot over the Palomar Knot is that you can tie it anywhere you want, not just at the very end of your line. The Uni Knot does not require a loop to be passed over the very end of line like the Palomar.