Zoom icon Click to expand Tap to zoom Chevron down icon Chevron down icon Back Flex Heel by Petzl $39.95 Availability: translation missing: en.general.icons.icon_check_circle icon 6 in stock, ready to be shipped 1 2 3 4 5 6 7 8 9 10+ Quantity Chevron down icon Quantity Add to cart Spinner icon Looking for Local Pick-up? Choose a store below. Product Locator by Locally Notify me when back in stock Email address Email me when available BACK FLEX is a heel bail system. It allows any type of Petzl crampon to be used with shoes without heel welts. It is sold in pairs, to equip a pair of crampons.