Believe it or not this is one of the most commonly used spring units even though not many people actually know what it is even though they have heard a lot about it. It has springs which are hour glass shaped and these are linked from top to bottom by a spiral wire which runs across the finished unit.
In addition to the spiral wire there is also a retaining wire used which is clipped around the perimeter of the mattress, top and bottom and within the industry this is known by the term “rod edge”.
Added support is provided through the retaining wire to the edge of the mattress and the cheaper options will have a plastic rod edge rather than the metal rod edge and the really cheap ones will not even have a edging at all!
The wire used within the Bonnell Spring Unit has varying thicknesses and this is known as the wire gauge. You can easily tell how thick or how thin the wire is and also how soft or hard the mattress will be by this wire gauge number; the higher the number the thinner the wire is and thus the softer the mattress. Obviously the reverse of this being the lower the number the thicker the wire and the more firm the mattress is.
Most of the Bonnell Spring Units will use a 13 gauge wire although some of the ortho models will use a 12 gauge or a 12.5 gauge so that a firmer spring is achieved. In most cases a standard double mattress will on average have 288 Bonnell Springs and you can measure the quality of the mattress then from gauge and also amount of filling used.
You should come to one of Prestige Bed’s showrooms if you are still confused and have a member of our expert and highly knowledgeable team explain it to you. We take the time to listen to our customers about what they require and what they are looking for before we advise of what options are available.