The seat slider is the device that adjusts the seat pan forwards or backwards. It is essentially a ratchet back feature for the seat. The seat slider helps the chair adjust to the user, not vice versa. Its importance to a chair's overall ergonomic nature can be determined by the type of seat cushion in the chair. This feature can help adjust the user so that they are getting full use of the waterfall feature on the front of the seat, as well as provide the user the ability to fit into the contours of the seat comfortably. For taller people, the seat slider is great, as it adjusts the seat to the right depth.
Final Word: If used properly, the seat slider can add more comfort and customize the office chair to the user. Most ergonomic chairs will have this as an additional option. The seat slider in terms of ergonomic benefit is great because it gives the user an additional adjustment, to make their office chair fit their needs.