Hi BobP,
I would be very cautious with this mattress. The guidelines I would suggest for memory foam mattresses are listed in post #10 here and the Sleep Science Emma uses 3" of 3 lb memory foam (and 2" of 1.5 lb polyfoam under that) which are both low quality less durable materials and Sleep Science is manufactured in China and isn’t CertiPur certified which means that it doesn’t meet two of the criteria that I would personally consider to be the minimum standards for a memory foam mattress (one for the quality of the foam and one for some reasonable assurance of its safety).
Post #6 here would also be worth reading for any mattress that is manufactured in China.
Phoenix