You probably won’t find this technique in a basic rock climbing book. Erik Eisele stashing his helmet to facilitate upward progress in The Beast (5.11+) chimney on Cathedral Ledge in New Hampshire. The second photo gives a better perspective of the route.
Photo Details: Canon 5D w/ EF 16-35mm f/2.8 L II USM lens at 35mm, 1/200s at f/4 and ISO 1000.
Photo Details: Canon 5D w/ EF 16-35mm f/2.8 L II USM lens at 16mm, 1/400s at f/4 and ISO 1000.