Say goodbye to one-size-fits-all and hello to the California King BEDGEAR M3 Performance Split Comfort Mattress - Firm & Soft! Taking Performance and innovation to the next level, the M3 is the worlds first dual-sided modular mattress that empowers you to choose your individual comfort level. Featuring our Air-X breathable mesh panels for 100% airflow and our instant cooling Ver-Tex top cover, the M3 is the best mattress for hot sleepers.