Hi,
for some old information, check Lars Gucks
pages.
Today, most use a two patch system. The lower patch has a small metal ring you thread the retrieval line trough, and you secure the end of the line in the top patch.
While dousing, the line slides trough the lower patch w/ring until the upper patch comes down to it and pulls it into the snuffer.
Most Tornados uses a two patch system, and has a snuffer about three meters long. It varies tough..