King size Sleep Number C2 mattress. Great mattress but my we needed a special mattress for his back issues and then we can sell this one. Bought brand new from Sleep Number last summer so it will be only 3 months old. Always had foam and cover on mattress. NO stains of any kind. Everything is effective (remote has batteries and works perfectly) and bed is able to go! Them of the bed could be adjusted separately so it’s an excellent bed to suit your needs.