Smoothie beadlock system with brake disk hub/ 12mm hex adapter. Wheels are 30mm wide and spaced for 42mm wide tires. Wheels assemble using (8) M3x8mm screws per wheel (48). Front wheels mount to hub with included width spacer using (8) M3x25mm screws (16). Rear inside wheel mounts to hub with (4) M3x10mm (8) screws rear dually adapter mounts to inside using (4) M3x18mm screws (8). Outside wheel mounts to inside wheel assembly using (4) M3x10mm screws and (4) M3x6mm screws for remaining holes. Required hardware for assembly :                                    (8) M3x6mm, (48) M3x8mm, (16) M3x10, (8) M3x18mm, (16) M3x25mm.

I recomend installing the brake hub and lock nut before mounting the wheels to the hub due to added depth requires a longer lug wrench or socket.