Grades of memory foam used in memory foam mattress and toppers.
When purchasing a memory foam mattress it is always best to check what grade of memory foam is used in the mattress. There are different grades that can be used as shown below:-
L grade - low grade memory foam.
A grade - Average grade memory foam.
S grade - Severe grade memory foam.
A memory foam mattress should idealy be made of A grade or S grade memory foam. Usually cheaper mattresses use the L Grade and i would suggest avoiding any mattresses made using this type of memory foam, as it will have a short lifespan and will not offer the support needed.