Flex: 8/10 M: Us 8-11 (40-44) L: US 11-14 (44-47) Aggressive Lightweight Performance. BMBW’s solution for aggressive snowboarders in challenging terrain. Lightweight Carbon Fiber provides the precision and power to put down the line of a lifetime. CARBON FIBER DRIVE PLATE Carbon Fiber sandwiches a hardrock UHMW to increase response, pop and keep things ultra light. CARBON FIBER HIGHBACK Composite materials like carbon fiber make an ultra light highback with a firm instantaneous response for precision in steep terrain.