Helix hybrid mattresses combine the best of foam and spring technology. Midnight provides a medium feel and is the most popular model. Mattress features top and middle layers developed to give the perfect support, including a Memory Plus Foam layer that's great for both stomach and back sleepers while offering the support needed for side sleepers. Breathable cover and hybrid design keep you cool while you sleep. -Made by Helix Sleep -Ships directly from vendor -OKEO-TEX and Certi-PUR certified -Memory Plus Foam, high-density polyurethane and innerspring coil unit -Individually wrapped steel springs with reinforced perimeter for edge support -120 Night Sleep Trial guarantee: Helix mattresses may be returned for a full refund within 120 nights, after the first 30 days -Llimited lifetime warranty -Made in USA of Domestic and Imported Materialsandlt;span id=andamp;quot;recycle-feeandamp;quot;andgt;** For orders shipping to California, Connecticut or Rhode Island, a recycling fee will be added to every purchase of a mattress, box spring or bunky board CA: $10.50 under California's Used Mattress Recovery and Recycling Act; CT: $11.75 plus Sales Tax under CT Public Act 13-42; RI: $16 plus Sales Tax under RI General Law 23-90. ***For orders shipping to California, we can pick up your old mattresses at no additional cost with every purchase of a new mattress. Please contact us at https://www.cb2.com/customer-service/ to schedule your pick up today. For Simmons mattresses shipping from the vendor, we will pick up your old mattress during the delivery of the new one. Helix Core Midnight Medium California King Mattress