The Open Ergonomics back support gives less support low down, helping to keep the pelvis at the back of the seat. Support is consistent and peaks correctly at the mid-point of the lumbar curve, before tapering off below the shoulders, which will help the back to relax. Support W is a rather flat shape in a hard foam, with a lot of protrusion. The high peak at around 170 mm is caused by the sacrum, which will tend to lever the pelvis forwards along the cushion. The variable support is caused by the firm surface, which does not absorb surface features like clothing folds.
Support is too slight in the lumbar region, failing to keep the spine in the correct shape.
Support Y is a foam pad, softer than W but still rather firm, and quite short vertically. It creates a pronounced bump of pressure up to 8 kiloPascals, which is too high for blood flow to be maintained in the skin. This would be too uncomfortable to endure for long, and most users would quickly discard this support. This Site is maintained by Open Ergonomics.