The Collins Queen Sleep Sofa features a 4.5 inch premier inner spring mattres with 13.5 gauge high carbon steel springs. It also features welted, rounded arms, box border inside back and seat cushions and tapered wood feet. The loose inside back cushions, loose seat cushions and throw pillows are all zippered for easy access if that were ever needed. The seat cores are 9.5 inches thick and feature a plush 1.8 density, 32 lb. HR compression foam core and Dacryon wrap. The inside back cushions are channeled and bagged with blown fiber and the throw pillows are bagged blown fiber. The sides of the sofa are padded for fullness in tailoring and a better look and feel.