This diagram makes choosing the mattress of HYPNOS series easier. Find the crossing point of the column and the line showing your height and weight. If the found point lies near the separating line, your choice will depend on how you feel. If you would like a relatively soft bed, choose a product for the lower BMI, and if a relatively firm bed is more to your liking, then choose the one for the higher BMI. The BMI span is marked on all Hypnos spring beds and mattresses.