The extra one inch thickness option refers to the additional inch being added to the bottom of the cushion, whether or not the cushion has an XS top. Note; however, that the extra one inch thickness cannot be added to cushions with a "Sling" bottom. ...
The Smart model is essentially a version of this manufacturer's Sport cushion, but with the softer XS top layer. It is made of the same perforated and breathable, open cell honeycomb structure as Supracor's other Stimulite cushions. The cushion's excellent breathability (as compared to other ...