The main difference between MT30671549 and MT30671561 is the specific model of the pH/ion meter in each kit. MT30671549 is the Mettler Toledo SevenDirect SD50 pH/Ion Meter LowVol Kit. The SD50 model offers pH and ion measurement capabilities and is designed for low-volume samples.
MT30671561 is the Mettler Toledo SevenDirect SD20 pH/ORP Meter LowVol Kit. The SD20 model provides pH and ORP (Oxidation-Reduction Potential) measurement capabilities and is also designed for low-volume samples. The key distinction between these two kits lies in the exact meter model (SD50 versus SD20) and the specific measurement functionalities they offer (ion measurement in the SD50 versus ORP measurement in the SD20).