Rondo This insert breaks the stereotype of a usual fire insert. It is no longer rectangular but round. Breaking the stereotype we allowed the flames to be viewed from all sides. Moreover, its design provides professionals with more freedom of arrangement as it can be easily placed in most horizontal locations. Rondo employs the patented Glassfire® Technology – the effect of dancing flames captured in a glass cylinder. The cylinder protects against any accidental contact with fire, what might be the key factor in choosing this model.