The Fring by Neutral Posture was specifically engineered to correct lower leg and foot positioning issues that can compromise blood flow to your lower extremities. Ergonomists consistently recommend against pulling your legs under your chair and resting them on top of your chair base. This is not recommended because the foot to shin angle is less than 90 degrees which constricts blood flow. It also places pressure behind the knees. This can lead to fatigue and even varicose veins, especially in shorter people.
The Fring resolves these issues by creating a position that angles the footrest so your foot to ankle angle is wider and allows for adequate blood flow and removes the pressure behind the knee.