The flexible, contoured ergonomic design gives you the choice, providing soothing relief to those experiencing discomfort in their lower back, buttocks or both. You choose to use it as a seat or a backrest! 
Use it as an ergonomic backrest or an ergonomic seating device
Its portability allows you to use it at home, in the office, in the car, or just about anywhere
To use the Sitback Cushion as a backrest, stretch the elastic strap over the top of a chair
To use the Sitback Cushion as a seat, stretch the elastic strap over the front of the seat of the chair