|One Wrap||Two Wraps|
The Carabiner Prusik can be tied with one turn as shown, or a second turn can be taken around the standing line. I find that the second turn is usually needed. The double turn version is closely related to the RBS knot, but the standing line passes through the carabiner and the sling makes about half a twist more around the standing line. The knot is easily tied: just clip the carabiner around the standing line, twist it downward, clip the sling and lock the gate.
Like most carabiner knots, the orientation of the carabiner with respect to the standing line does not seem to be particularly important. The knot is easily moved, but tends to fall if not loaded.