-4130 Chromoly crankset, tubular arms with smooth outer plate to reduce "ankle bite". The LH/RH compatable arms are heat-treated with Demolition's patented Thermo-Triton process. 19mm 48 spline chromoly spindle. Crankset includes arms, spindle and hardware only. Bottom bracket sold seperately. Weight: 29ozs.. The arms are guaranteed for life.