Shop › The Sentinel Original Oil Painting Image 1 of 2 Image 2 of 2 The Sentinel Original Oil Painting Sale Price: $115.00 Original Price: $150.00 This plein air study of an old tree is painted on a 10x8” canvas. It will be framed in a simple dark wood frame. Add To Cart Added! This plein air study of an old tree is painted on a 10x8” canvas. It will be framed in a simple dark wood frame.