CMC Rescue - Figure 8 Descender Rescue 8FEATURES Machined from 1 2 inch (12. 5 mm) plate, our classic Rescue 8 design has been refined for even better performance with today's selection of rescue rope. Descenders no longer routinely use 5 8 in (16 mm) rope, so the smaller dimensions of our Rescue 8 provide greater control. The proprietary finish on the aluminum model provides outstanding wear resistance, while the nickel chrome plated steel model excels in high wear situations, such as