The J-10B is a modified variant of the J-10 multirole fighter aircraft, with modifications in airframe and avionics. A J-10B prototype reportedly made its maiden flight in December 2008. The J-10B features a chin-mounted diffuser supersonic inlet (DSI) air inlet. The traditional rectangle-shape air inlet on the J-10 requires a large moveable inlet ramp to generate a rearward leaning oblique shock wave to aid the inlet compression process. The J-10B had an electronic-optic targeting system (EOTS) added. Placed forward of the cockpit canopy to the right, the system comprises an infrared search and track (IRST) sensor and a laser rangefinder, which can detect enemy targets passively without requiring to turn on the fire-control radar, thus reducing the chance of the aircraft being detected. The upper edge of J-10B’s tailfin is curved, in contrast to the straight-edged tailfin of the J-10. A large fairing is added to the tip of the tailfin to accommodate electronic warfare and countermeasures (EW/ECM) equipment.