Devices to reduce noxious exhaust emissions from combustion engines, namely inline valves, inline throttling valves, inline baffles and catalytic converter heaters; devices positioned in the exhaust flow of a combustion engine and to reduce pollutants in the exhaust, namely inline valves, inline throttling valves, inline baffles and catalytic converter heaters; devices to radiate or transmit heat to a catalytic converter in an exhaust system, namely inline valves, inline throttling valves, inline baffles and catalytic converter heaters; devices to radiate or transmit heat to a catalytic converter in an exhaust system and which absorbs the heat from the exhaust gases and reradiates the heat to the catalytic converter in the exhaust system, namely inline valves, inline throttling valves, inline baffles and catalytic converter heaters; all the foregoing being for petrol or diesel engines; devices to treat fuel in combustion engines; devices positioned in the fuel train of a combustion engine to reduce pollutants in the exhaust and maximise efficiency of combustion; magnetic fuel treatment devices including in-line treatment devices; fuel treatment devices utilising magnets; all the foregoing being for petrol or diesel engines