MERRITHEW Foam Cushion Available in 3 Sizes: Foam Cushion A (6-inch  9-inch  1-inch), Foam Cushion B (6-Inch  9-inch  3-inch), Foam Cushion C (10-inch  13-inch  2.5-inch) Foam Cushion "A" is ideal for the head and for seated exercises; Foam Cushion "B" is ideal for the knees and ankles or in side-lying positions on the STOTT PILATES reformer; Foam Cushion "C" is ideal for seated exercises for added height Designed for extra comfort and support when performing a wide variety of exercises Allows for proper alignment and biomechanics Made of high-density, closed-cell polyethylene foam