It is indicating that the chair tilts back and fourth. That is incorrect. There are actually conflicting descriptions. And then I get information back from the company stating that a knob under the chair is for tilt. We used that and all it does is create tension in the actual base of the seat. That is not what tilt feature means. My wife got this for back issues and in that it is stated a ergonomic at the actual cost, not the sale price, this should be able to adjust the back so you are not having to lean forward. The lumber feature prevents you from sitting strait in the seat while working. We are still trying to see if we can use this chair without issues.