"Extra Firm There are different mattress comforts: soft, mid- firm, firm, very firm and extra firm. But how to choose the firmness that is right for you? Firmness is chosen in regard to an important criterion: the morphology of the sleeper. The greater it will be important more it will be necessary to equip a firm mattress (see extra firm). To make this choice, it is advisable to take the time to try it in a comfortable way. To try a mattress means to lie on it and to take the time to try it in different postures, on the side, on the back, sitting up, etc. The extra firm mattress is suitable for people who sleep on the back and for morphologies from 100 kg upwards. "