Sierra Designs asked us to explore innovative volume expansion and load compression for waist carry on the trail. Working from SD’s proprietary Flex Capacitor materials and functionality, we investigated optimal ways of managing variable loads with maximum comfort and ease of access. Offered in two sizes 6LT and 10LT, both allow for a 4LT flexible volume control for ultimate stability against the body as jackets, bottles and food go in and out of the pack during a run or bike sesh. The expandable center design is an updated construction of the current FC which increases build quality and versatility while decreasing weight and cost. Both models have been concepted with a new style of mono-hip belt with skived foam to maximize contouring and support over the center of the sacrum while allowing lightweight flex around the hip. The 10LT concept features a special PE back panel insert that allows the pack to maintain structure for optimal transfer of weight across the lower back while also adhering to the user for a comfortable fit.