Compatible only with ski boots using the XP interface Best paired with wide nordic backcountry skis with waist widths of 65mm to over 100mm Spring pin connection allows easy step-in and exit with boots, and resists clogging with snow Connection with boots creates stronger steering and easier forward striding A 36mm heel lifter for ascending steep slopes is included The argument is now closed. What is the best cross country ski binding system for backcountry, 75mm Three-pin or NNN-BC? Neither. The best attributes of both are incorporated into the Rottefella Xplore binding system. A true walking sole for ski trips that have sections without snow or demand kicking steps. A step-in feature that won't get compromised with packed-in snow. A pivot point that allows for an effortless forward stride without crunching toes. And the width of the boot and binding connection creates powerful ski steering and downhill control.