The cells are more irregular and differently-sized. Scientific studies* confirm that the more irregular the cellular material, the better the ELASTIC performance of the material. A perfect twelve-sided structure.
It can be said that Bultex®’s elasticity is optimal in response to sleepers’ movements during rest.
* Study by X.Zhu, JR. Hobdell & AH. Windle - Department of Materials Science and Metallurgy, Cambridge University..