The Macnaught IM series flow meter is an inline oval gear meter designed specifically to measure lubricating oils . The IM series is compatible with oils up to SAE140, automatic trans fluid, engine oil, gear oil, hydraulic oil, coolant, diesel, or kerosene . Available with two port sizes, the IM series has a flow range of 1 to 30 L/min with 1/2" port or 3 to 80 L/min with the 3/4" port. BSP or NPT threads are available .

The rugged body can withstand working pressures of up to 1000 psi for the smaller meter and 1500 psi for the larger. The IM series has a working temperature range from -14° to 55°C .

The IM series is also available with a choice of mechanical register, electronic display, or pulse output. The mechanical register option includes a 4-digit resettable batch totalizer as well as a 7-digit accumulative totalizer, with ±1% accuracy. The electronic display option includes a 6-digit digital display with resettable batch totalizer and non-resettable totalizer, achieving ±0.5% accuracy. The pulse output model includes a one-meter fly lead with reed switch output and can also achieve ±0.5% accuracy .