Browse by Smart Bonnell, brought to you by F31, Singapore’s top online furniture shop. What is a Bonnell type of mattress? A Bonnell Mattress refers to the type of mattress that has springs underneath all of the foam and fluff that makes the bed swift and comfortable. A Bonnell spring coil is hourglass shaped to give it the maximum support for the user, the Bonnell spring to create durable and supportive mattresses. Choose wisely as you will spend ⅓ of your life sleeping on this mattress; Bonnell Springs or not, F31 carries professionally made mattresses all year long.