Build-up Blocks is the measurement system you need for accurate lift information. Lower back, hip and knee pain can occur if the child has uneven leg length. Use Build-up Blocks to help determine if your patient needs heel lifts to equalize their limb length. By simply stacking lifts inside the Build-up Shoe, you can adjust the height. Just stack and add! Each lift is lightweight and comes in 5 fabulous colors: Brown (0.25"), Yellow (0.5"), Red (0.375"), Blue (0.625"), and Black (1"). If your patient is required to walk with the added elevation, the hook and loop straps can be used to easily secure Build-up Blocks to the foot. Please note, no foot designation is required because Build-up works on both the left and right foot.