Pulley 2 : A device with a free-turning, grooved metal wheel (sheave) used to reduce rope friction. Side plates are available for a carabiner to be attached
NFPA 1670 Standard on Operations and Training for Technical Search and Rescue Incidents, 2009 ed. https://www.nfpa.org/assets/files/AboutTheCodes/16 70/Errata1670-09-1.pdf, (Std: Opr and Trng for Tech Search and Rsq Incid - Amer) {408 NFC}