ETONEX 12 Inch Twin Mattress Cooling Gel Memory Foam and Pocket Spring Hybrid Mattress in a Box Medium Firm CertiPUR-US Certified Foam (Twin, 12in) Twin 12" Hybrid is up for auction in Home & Kitchen. The current bid is $40.00, 69% below the $129.98 MSRP, in New/Like New condition. This auction has ended — similar items appear in live auctions regularly.