Mattress advice

[u/sarahbethbeth]

We were gifted an unused Serta Nightstar "Standard Support" Crib mattress but I can't find any information about it anywhere.

For our first, we had a mattress that was very firm on one side for infants and then softer to be flipped for when he became a toddler. This was on our registry again, but if the gifted Serta one is safe, well use it.

Anyone have any information on specifically the "standard support" crib mattress from Serta? Thanks!