FabStretch® 4-Level Incline BoardFabStretch 4 Level Incline Board Heavy Duty Plastic 5, 15, 25, 35 Degree Elevation 14" x 14" Surface Slant Board increases extension in the lower and upper back while stretching the calves. Board is made of a heavy duty composite plastic. Angle of incline adjusts to 4 levels and folds flat (3 inches) to store easily. Levels are 0, 5, 15, 25, and 35. The last slot on the board makes an excellent hand hold for stretching. Non slip top measures 14" x