We found this article interesting and extremely educational on the details of operating the Two-Tensioned Rope Rescue System (TTRS). Published in the Fall 2015 issue of the Mountain Rescue Association’s publication The Meridian, this was material Kirk Mauthner presented at the International Commission for Alpine Rescue Congress in Ireland earlier that year.
Although the article was written with a specific reference to the MPD, please understand that the MPD is not the only tool of choice for two a TTRS. While Mauthner was the designer of the MPD, we now have the Petzl MAESTRO and the CMC Clutch. The principles covered in the article can apply to all three of these devices.