http//orthoseat.com/folding-chair-portable-folding-seat/

I just discovered the OrthoSeat, a portable chair that has been a familiar sight at camp sites since 1989! It's made from rubber tree wood slats (lightest of the hardwoods) and durable 100% cotton canvas. The Orthoseat folding chair supports the back properly— which allows you to sit for extensive\long periods of time without stiffness. I can see why this portable folding seat has enjoyed such widespread approval over such a short time. It's terrific!