Ottobock C-Leg 4 is the fourth generation of Ottobock's microprocessor-controlled prosthetic knee — the global market-leading powered prosthesis for above-knee amputees. The C-Leg uses hydraulic and electronic control to continuously adapt knee resistance to gait phase, terrain, and walking speed in real time, enabling amputees to walk on slopes, stairs, and uneven terrain with significantly reduced fall risk compared to mechanical prosthetics. Cleared by the FDA and deployed in over 150 countries, the C-Leg 4 is the reference standard for microprocessor prosthetic knee technology.