It is important to use a knee pillow when beginning to "exercise" on the Chi machine. If you have serious neck/back, hip or knee issues..you may need to use 2 or 3 knee pillows to reduce mobility in the beginning. Many use the knee pillow because it is designed to help provide ideal spinal alignment and reduce discomfort, decrease pressure/strain and to improve circulation.
We have the Knee Wedge by Alex available in blue or sand.
The pillow is wedge shaped polyurethane foam(17"x 10" x 6"). It has a removable cover that may be washed.