I use them on all my tops and whip them onto my whips as well.
Advantages are, they are basically free, a 15metre spool of 15lb dacron is about £3.00 and you only need about 100mm for each connector. When the hook pulls and the 'lastic comes flying back in there is no hard connector to smash into the tip of your pole.
To make one is simple, cut 100mm of dacron, and tie it into a small loop.
Tie a crows foot in the end of your 'lastic, put the dacron loop round it.
Cover the connection if required, with something, I use old catapult elastic.
To use it, tie a double loop in you rig and fit it.
This explanation is cr4p. I will go and take some piccies.
---------- Post added at 08:08 ---------- Previous post was at 07:19 ----------
Sorry my camera skills aren't good enough so here goes a long wordy explanation.
Tie a crows foot in your elastic (this is instead of a stonefo). You can connect the line (as explained in a minute direct to this, but I worry about the line cutting into the elastic). To tie a crows foot, tie an overhand loop in the elastic and cut the tag end and the loop to all be the same length, (say 8mm). I f you look at this you will see the leg (your main elastic), the foot (the knot) and the toes (the three ends).
Take a length of darcron (I find about 100mm ok) and tie a loop about about 30mm long with a figure of 8 knot (I always use a double figure of eight). Trim the tag ends.
Now take your dacron loop and put the knot through the loop, thus forming a loop (is that clear?) and pass the crows foot through the loop. Now wet and tighten the dacron down over the elastic (by pulling on the dacron knot) and slide it up behind the crows foot.
You should know have the darcon protruding at right angles to the elastic. I now fit a short length of old catapult elastic over the crows foot so that the dacron knot just protrudes and the crows foot and tag ends are covered. The only thing that now touches the pole is the catapult elastic.
To connect your rig, tie a loop in the end of your rig (once again I use a double figure of eight) and then tie another loop in the end of the first loop (double figure of eight). Cut the tag end from the first loop and cut the top of the loop from the second loop (the second loop is used to free the rig from the dacron by pulling on the second loop, and you don't want the second loop catching in snags and freeing the rig whilst fishing, snipping the loop prevents this).
Form a small loop by pulling the main line of your rig into the first loop and slip this small loop over the dacron knot. Wet and pull tight. Jobs a good'un.
To release the rig pull on the two tag ends on the rig created by snipping the second loop earlier.
Blimey, I need to go and lie down.
---------- Post added at 08:44 ---------- Previous post was at 08:08 ----------
This might make it a bit clearer
YouTube - Steve Mayo-Maver Dacron Connectors