Hanging Knee Raise. How-to, proper form and tips

The Hanging Knee Raise is a strong core exercise that simultaneously strengthens shoulders and grip, making the exercise a good core and upper body combination.
Video demonstration
(excerpt from 'Hanging Knee Raise Tutorial - True Form'
by The Health Alchemist)
How to and step by step instructions:
- Hang on the bar, hands shoulder-width apart.
- Raise the knees until they almost touch the chest.
- Slowly extend the legs returning to the starting position.
Hints & tips:
- Make the move slowly, avoid any balance movement.
Benefits:
- Strengthens abs and upper body.
Counting & gamification:
- Count repetitions per period, such as week or month.
- Aim for a 3x10 repetitions.
Muscles worked and body parts involved:

Muscles: Full body
Primary muscles: Shoulder, Forearms, Hand, Abs, Hip Flexor
Secondary muscles: Obliques, Upper Back