These are easy options for adding friction or a stopper.

Tonight I climbed about twenty feet with two of these in-line lanyards. After trying it many times, the slip knot placed in front of the attachment knot is essential. It adds the needed friction to prevent slipping. Moreover the system becomes self tending when slack is taken up.

This system fits with the climbing needs. It can be tied during the ascent, replacing one of the safety slip knots.

It unties with a steady pull of the down rope, because it's a series of 3 loops.

The big benefit remains: the climbing rope can be used to make multiple lanyards, allowing a more efficient advancement.

Hi Spiderman,

To add friction, a slip knot is formed on the existing loop. In a slip knot loop, one side is stationary and the other side moves. This is how to form the knot that you're talking about: 1) form a loop on the stationary side 2) pull the moving side through.

Once you hit on the correct sequence, you'll see that you can continue to add multiple slip knots along the way. The other sequence is simply a hard knot and nothing moves.

I'll be glad to make a photo if that helps.