- Product Line
- Classic
- Regency
- Orthopedic
- Serenity
- Design Type
- Pillow top
- Foam
- Hybrid
- Currently shopping by:
- Mattress Size: Twin XL or Full or California King
- Product Type: Box Spring
- Design Type: Two-sided
The Original Mattress Factory offers a wide selection of hand-built king-size mattresses. King-size mattresses are 76 inches x 80 inches (± 1 inch). Our king-size mattresses are available in 15 innerspring and three foam models, including two-sided and one-sided models and in comfort levels from soft to hard. We highly recommend you pair your new mattress with a real working box spring, as well as a heavy-duty frame that features a center rail for support. Split box springs come standard on all king-size mattress sets. If you have concerns about being able to easily get in and out of bed due to the height of the mattress, you may want to consider a low-profile box spring. All OMF king-size innerspring mattresses are hinged to enable you to fold the mattress for easy transport.