The Motion Arm is the first IP67 dustproof, waterproof Automatic Forearm Balance Hybrid Elbow. Designed to be the most robust elbow available; the ML combines a body powered lock/unlock system with a 3000 mAhr internal battery. Able to support up to 50 foot pounds in the locked position this elbow is up to all tasks. The Motion Arm EL has an electric lock/unlock with 3 EMG trigger options and/or the use of an external switch. Able to support up to 50 foot pounds in the locked position this elbow is up to all tasks.