I have heard a lot of information regarding the use of figure-8's, Petzl Stops, and rack for vertical descents. I think an 8 will serve my purpose, but i was also considering a Petzl I'D due to it's ease of use and attachment to the rope. I am a Marine Repair technician and routinely have to climb up masts to perfom work. I use a pair of Petzl Ascesions for this, but repelling with them is a pain. Heights above 100' are rare but not enitirely uncommon. Most climbs are in the 40-60' range. Any feedback would be helpful.