This technology works by placing a panel of ceramic glass across the front of the fire. This prevents Air from being drawn from the room through the fire opening and then up the flue. As a result, a very high proportion of the radiant heat from the fire is concentrated into the room.Glass fronted Imperium fire with Cast Trim in Black, Brass, Brushed Steel & Chrome87% efficient Slide control operationMid Depth inset gas fire suitable For Brick chimneys or Pre-Fabricated flues5 year warrantyHeat Input: 4.3kW (high) | 2.5kW (low) Heat Output: 3.4kW (high) | 2.0kW (low)The Smartslide Control is used to turn the fire on and off and regulate its flame level. Mounted on the side of the fire, the control provides convenience of operationImperium with Cast trim Width: 510mm Height: 630mm Depth: 128mm Inset Width: 402mm Inset Height: 553mm Cast Iron has always been a material of choice For fires because of its heat retaining properties. The Cast option is unmistakably sturdy. With many chunky characters, it also has an elegant side shown by the tapering trim and slender bands across the fret.