This is a souvenir lawn or beach lounger backrest originally purchased at the Vancouver folk music festival. The lounger has a wood frame and a canvas backrest with Vancouver folk music festival logo on it.

It's got three positions and the canvas comes out several inches in the front so that you don't sit directly on the ground when you lean back against this.

I believe the purpose of this lounger is so that the people behind you at the festival can still see the stage.