This mattress was put on a daybed I purchased from Wayfair. I had purchased 8” for top but found it would take a 10” so changed 8” to trundle. It is so comfortable and just right amount of firmness.  
My 3 yr old granddaughter used it when she spends the night. I lay down with her till she went to sleep. I feel asleep before she did and would have probably slept all night had my husband not woke me up!!!!