Open coil mattresses use one of the most long-standing methods of construction. Most people have slept on an open coil mattress at some point in their lives, and they are still some of the most widely-available mattresses on the market. Their construction means that they provide the support you need, whilst leaving plenty of room for a variety of fillings that help to provide you with comfort as well as support. How an open coil mattress works Open coil springs are usually about 5-6 coils high. A standard double bed has 325 of these coils, although some manufacturers may use more and, of course, the coil count increases as the mattress size rises to king and superking. The coils are all assembled into a single construction with helical wire. This is a thinner, spiral wire that joins the coils at top and bottom to form several rows. An outer rod is then fitted around the top and bottom of the finished construction to provide additional strength. Once the basic construction is completed, the mattress can be filled and the ticking applied. Variations As with most sprung mattresses, the tension, or firmness of the mattress can be altered by changing the thickness of the wire, the number of twists in the coil and the number of coils overall. In addition, an extra row of springs may be added at key points across the mattress to provide additional support. The continuous spring mattress uses the same basic construction principles as the open coil, but is made from a single length of wire that is essentially "knitted" together to form a single, sprung construction. The finished mattress springs are in rows, as with open coil, but are joined vertically. These springs are usually smaller than those used in open coil and use narrower wire, which makes them slightly softer. The fairly simple construction of the open coil mattress means that it is one of the most cost-effective mattresses on the market. If you are looking for a budget mattress, you will find a range of open coil mattresses that are both comfortable and affordable. Mattress Next Day is probably the largest mattress superstore on the internet. Selling a wide range of mattresses from leading manufacturers, we can offer quality mattresses at fantastic prices. Our next day delivery service is free or, if you prefer, you can select your own delivery date. We can even guarantee delivery before 9.30am on request. Take a look at our range of mattresses now at www.mattressnextday.co.uk, or call us on 0844 3911 222 for more information.