Hydrogen isotherms for MOF-177, Zn4O(1,3,5-benzenetribenzoate)2, crystals were independentlymeasured by volumetric and gravimetric methods at 77 K to confirm its hydrogen uptake capacityand to establish the importance of calibrating gas adsorption instrumentation prior to evaluatingH2 storage capacities. Reproducibility of hydrogen adsorption experiments is important becausenon-systematic errors in measurements can easily occur leading to erroneous reports of capacities.The surface excess weight percentage of hydrogen uptake in MOF-177 samples is 7.5 wt% at70 bar, which corresponds to an absolute adsorbed amount of 11 wt%. These values are inagreement with our previous report and with those found independently by Southwest ResearchInstitute. Considering its well-known structure and its significant H2 uptake properties, we believeMOF-177 is an excellent material to serve as a benchmark adsorber.