What is the difference between E-IR-R304A and E-IR-R304B?

Since PVDF membranes have two pore sizes, which are suitable for transferring target proteins of different molecular weights, we have designed two specifications in order to meet different experimental needs. E-IR-R304A (PVDF membrane 0.45 μm pore size) is recommended for the detection of proteins with a molecular weight greater than 20 kDa E-IR-R304B (PVDF membrane 0.22 μm pore size) is recommended for the detection of proteins with a molecular weight less than 20 kDa.