Zinus 6 Inch Foam and Spring Mattress / CertiPUR-US Certified Foams / Mattress-in-a-Box, Narrow Twin 4.4 out of 5 stars 13,799 $84.98 - $756.87 source https://www.amazon.com/Zinus-Spring-Mattress-Narrow-Replacement/dp/B074Q6T8NS/ref=zg_bs_1063306_25/138-1276153-8891202?_encoding=UTF8&psc=1&refRID=7ZBEJ3PNX2BSDV767RTZ
