Hardness and density
What is 35-45 hardness?
EVA mats can be made to any firmness, i.e very soft for children playing areas to very hard, for example a free weights area.
The standard hardness for martial arts mats is 35-45 degrees.
This measurement is not a sign of quality, just the firmness of the mat. (35 degrees is slightly softer than 45 degrees)
What is density?
The foam density is not in fact a weight but a measurement of mass per unit of volume and it is measured in kilograms per cubic meter (kg/m3)
Basically, the higher the density of foam, the greater level of impact resistance.
The impact resistance is the ability to push back against weight and prevent the foam from bottoming out.
This means that the higher the density, the better the quality of mat.
Martial Mats always recommends 120kg/m3 as this is very good at not just making a soft landing but more importantly absorbing much of the impact.
We would always recommend our premium grade jigsaw mats at the higher density of 120kg/m3, however, we appreciate customers may be looking for a lower cost alternative option. This is why we have introduced our standard jigsaw mats. These are still a very high quality mat as we will not sacrifice quality for price, but they do have a slightly lower density of 90-100kg/m3
If you manage to find cheaper than Martial Mats mats then please do check with the supplier what the density is (if in doubt ask for a sample).
As I am sure you will guess it is in fact cheaper to manufacturer lower density mats as you can add cheaper materials than EVA to the mat, therefore lowering the quality of the mat and reducing the life expectancy.