Single Rope Technique. SRT is a way of getting up and down vertical
pitches inside caves in a way similar to
rock climbing, using a harness, a descender (usually an
auto-lock descender such as a
Petzl stop) and two or more
ascenders (jammers). This is attached to, as the name suggest, a single
rope which you hope doesn't break.
Going down the rope (abseiling) is very easy, whilst going up the rope (prussiking) is a lot more energetic, but still can be fun.
Much fun can be had, especially with badly rigged rebelays and light failures.