HOIST Fitness RS-1700 Chip/Dip Assist 

The ROC-IT Multi-Grip Pull Up Station uses a counter-weighted assist platform. Users can chose to offset any portion of their body weight with the machine's weight stack or remove the platform to use their entire body weight. This makes it an ideal solution for both beginner and advanced users.
It features adjustable dip handles to accommodate varying body types and offers a variety of positions; wide and, narrow grip positions, plus rock climbing grips that develop wrist, arm and shoulder strength more effectively than with traditional pull-up bars.
HOIST's ROC-IT Multi-Grip Pull Up Station also features a adjustable inner grips . These rotate, allowing users to perform both neutral grip pull-ups and narrow grip chin ups.