In a good quality inner spring mattress, the support for the back is provided by the coil spring unit. The comfort level is created by using different layers of padding. Many people associate a harder mattress with firmer support. Firmer support in a mattress set will come from a better quality spring unit. A harder feel in a mattress will create the effect of being more on top of the padding. With a firm coil spring unit offering support and the harder type of padding, a firm mattress can offer a comfortable night sleep to many sleepers. Mattress City offers these firm mattresses in three quality levels: standard, premium, and luxury. The product levels very by the amount of support that is provided and the type of padding on the mattress.