Qmark Wide range of optional control kits are field-installable, increasing the unit's adaptability to specification market Small- to medium-case construction is 20-gauge steel with larger cabinet 18-gauge steel Advanced pull-through air flow design draws air across heating element for even air distribution and cooler element operation Specially designed venturi outlet to meet required additional air throw in vertical position Branch circuit fusing (when required) Completely enclosed fan motor 2-speed fan selector switch (25 to 50 kW models) Optional fan-only switch for air movement with no heat or 3-phase wiring on 5 kW through 10 kW 208/240V and 15 kW 208V units (field-interchangeable) Aluminum-finned, copper-clad steel sheath heating element extends life due to cooler sheath temperature and faster heat dissipation 24V control transformer standard on most models, providing safer and more accurate means of temperature control. 3 kW and 5 kW, 208-277V, have line voltage controls as standard (24V control available on made-to-order basis) Automatic reset linear thermal cut-out, capillary type, provides protection over entire length of element areas (manual reset protection available on made-to-order basis) No piping flues, valves or traps needed for installation Individually adjustable louvers to direct air flow *