The difference is that the former ones only have the flow measurement function but the latter ones also have the flow control function.
*If you need both the flow measurement and control functions, please select a mass flow controller.
*If you need only the flow measurement function, please select a mass flow meter.

SCCM is the Standard Cubic Centimeter per Minute and represents the value of cc/min at the temperature of 0ºC under the atmosphere pressure. SLM is the Standard Liter per Minute, which represents the value of L/min under the same conditions.
Although the mass flow meters and controllers measure the mass flow rate, the volume flow rate is used as the unit because the flow rate is generally expressed in terms of volume.
In the semiconductor industry, the temperature of 0ºC under the atmosphere pressure is defined as the standard condition. In some of the other industries, however, the temperature of 20ºC under the atmosphere pressure is defined as the standard condition, and the flow rate at the temperature of 0ºC under the atmosphere pressure may be represented as NCCM/NLM.
When placing an order for our mass flow product, please specify the standard temperature and pressure (e.g. SCCM (0ºC, 1 atm) or NLM (0ºC, 1 atm)).

It is the difference between the primary-side and secondary-side pressures with which the mass flow controller can perform normal operation.
*Please refer to the specification sheet on the catalog for the operating differential pressure range of each product.
*The product may not perform normal operation with a differential pressure that is out of the range specified in the product specifications.

Please tell me the serial number on the label.