The largest of Chouinard Equipments pitons, these aluminum 4 inch Bongs were used when the climbing became wide and gnarly. One of ours came to us from an old El Paso County (Colorado) equipment cache, another came from Harvey T. Carter and was given to me before a trip to the Mystery Towers in Utah, the last was a donation from a climber in Northern California and was used in Yosemite Valley in the early 1980s.